Liquid crystal display device

ABSTRACT

A display device having a display element is configured such that the extending directions of electrodes are made different from each other among upper, lower, left and right pixels.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a Continuation of nonprovisional U.S. applicationSer. No. 11/098,516 filed on Apr. 5, 2005. Priority is claimed based onU.S. application Ser. No. 11/098,516 filed on Apr. 5, 2005, which claimsthe priority of Japanese Application 2004-115337 filed on Apr. 9, 2004,all of which is incorporated by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a display device.

2. Description of the Related Art

A display device has tasks which have to be steadily improved such asthe enhancement of brightness, the improvement of a viewing angle, theenhancement of image quality, the enhancement of a yield rate, theenhancement of reliability, the enhancement of productivity, thereduction of cost and the like. Here, with respect to the improvement ofthe viewing angle, for example, U.S. Pat. No. 6,256,081 disclose adisplay device which sets the directions of electrodes in a plurality ofdirections in the inside of one pixel or U.S. Pat. No. 6,456,351disclose a display device in which the directions of electrodes are madedifferent in three pixels which are arranged close to each other in thelateral direction.

SUMMARY OF THE INVENTION

As has been explained in the Description of the Related Art, the displaydevice has the various tasks which have to be steadily improved. Amongthese tasks, with respect to the viewing angle, for example, inventorsof the present invention have found out that the structure shown in U.S.Pat. No. 6,256,081 generates an invalid region on a center portion of apixel and lowers the brightness. Further, the inventors of the presentinvention have found out that the arrangement of the U.S. Pat. No.6,456,351 exhibits an insufficient viewing angle at the time ofdisplaying a monochroic color corresponding to a color filter of red,green or blue.

The present invention has been made under such circumstances, forexample, and one of advantages of the present invention is to provide adisplay device which can enhance a viewing angle and can realize theenhancement of brightness in both of a white display and a monochroicdisplay.

Although there are many other tasks and advantages which the presentinvention aims to achieve, these tasks and advantages will becomeapparent by the disclosure made in this specification and attacheddrawings.

To briefly explain the inventions disclosed in this specification, theyare as follows.

(1) In a display device having a display element, for example, thedisplay element is configured such that the extending directions ofelectrodes are made different from each other among upper, lower, leftand right pixels.

(2) On the premise of the constitution (1), the extending direction ofthe electrodes in each pixel is unidirectional.

(3) On the premise of the constitution (1) or (2), the pixels includetwo types of pixels in which the extending directions of the electrodesare symmetrical with respect to the gate-signal-line extending directionor the video-signal-line extending direction, and the pixels arealternately arranged in the upper, lower, left and right directions.

(4) On the premise of any one of the constitutions (1) to (3), thedisplay element includes color filters having three primary colors andthe color filters are arranged such that the color filters of the samecolor are arranged in the longitudinal direction of the display deviceand the color filters of three primary colors are sequentially arrangedin the lateral direction of the display device.

(5) In a display device having a display element, for example, thedisplay element includes lower planar electrodes and upper electrodeseach of which has a large number of line-like portions or slit portionswhich are formed on a same substrate, and the extending directions ofthe large number of line-like portions or slit portions are madedifferent from each other among upper, lower, left and right pixels.

(6) On the premise of the constitution (5), the extending direction ofthe line-like portions and the slit portions in each pixel isunidirectional.

(7) On the premise of the constitution (5) or (6), the pixels includetwo types of pixels in which the extending directions of the line-likeportions or the slit portions are symmetrical with respect to thegate-signal-line extending direction or the video-signal-line extendingdirection, and the pixels are alternately arranged in the upper, lower,left and right directions.

(8) On the premise of any one of the constitutions (5) to (7), thedisplay element includes color filters having three primary colors andthe color filters are arranged such that the color filters of the samecolor are arranged in the longitudinal direction of the display deviceand the color filters of three primary colors are sequentially arrangedin the lateral direction of the display device.

The display device having such constitutions can enhance a viewing angleand can enhance the brightness in both of a white display and amonochroic display.

Other advantageous effects which are realized by other constitutions ofthe display device disclosed in this specification will become apparentbased on the disclosure in this specification and attached drawings.

DESCRIPTION OF THE DRAWINGS

FIG. 1 is a plan view for explaining an arrangement example of a groupof pixels of a display device according to the present invention;

FIG. 2A and FIG. 2B are views for explaining an example of a pixelpattern of the display device according to the present invention;

FIG. 3 is an explanatory view of an example of the correspondencebetween color filters and a group of pixels of the display deviceaccording to the present invention;

FIG. 4 is an explanatory view of an example of the correspondencebetween color filters and a group of pixels of the display deviceaccording to the present invention;

FIG. 5 is a plan view for explaining an example of a group of pixels ofa display device according to the present invention;

FIG. 6A and FIG. 6B are plan views for explaining an example of a groupof pixels of a display device according to the present invention;

FIG. 7 is a plan view for explaining an example of a group of pixels ofa display device according to the present invention;

FIG. 8A and FIG. 8B are an explanatory view of an embodiment of thearrangement and the orientation direction of a polarizer;

FIG. 9 is an explanatory view of one example of the detailed structureof the pixel of the display device according to the present invention;

FIG. 10 is a an explanatory view of one example of the detailedstructure of the pixel of the display device according to the presentinvention;

FIG. 11 is a schematic cross-sectional view of an A-A′ portion in FIG. 9or FIG. 10;

FIG. 12A and FIG. 12B are views for explaining the getting-over at anoverlapped portion of an electrode and a line;

FIG. 13 is a schematic cross-sectional view of a B-B′ portion in FIG. 9or FIG. 10;

FIG. 14 is a schematic cross-sectional view of a C-C′ portion in FIG. 9or FIG. 10;

FIG. 15 is a schematic cross-sectional view of a D-D′ portion in FIG. 9or FIG. 10;

FIG. 16A and FIG. 16B are explanatory views of a display region and adummy pixel region;

FIG. 17 is a schematic explanatory view for explaining the arrangementof pixels at corner portions;

FIG. 18A, FIG. 18B, FIG. 18C and FIG. 18D are explanatory views forexplaining the arrangement of electrodes of the pixels at the cornerportions;

FIG. 19 is an explanatory view of an example of the dummy pixel region;

FIG. 20A and FIG. 20B are schematic cross-sectional views taken along aline A-A′ and a line B-B′ in FIG. 19;

FIG. 21 is an explanatory view of an arrangement example of a dummypattern in a dummy pixel region;

FIG. 22 is a plan view of the arrangement example of the dummy patternin a dummy pixel region;

FIG. 23A and FIG. 23B are cross-sectional views for explaining anexample of a dummy pattern;

FIG. 24A and FIG. 24B are cross-sectional views for explaining anexample of a dummy pattern;

FIG. 25A and FIG. 25B are cross-sectional views for explaining anexample of a dummy pattern;

FIG. 26 is a view for explaining a schematic example of a system of adisplay device

FIG. 27 is an exploded perspective view showing one example of themodule structure of the display device;

FIG. 28A to FIG. 28E are views of the module of the display device asviewed from a front side, an upper side, a lower side, a left side and aright side in a state that the display device includes an upper frame

FIG. 29 is a view of the module of the display device as viewed from aback surface;

FIG. 30A to FIG. 30E are views of the module of the display device asviewed from a back surface, a front surface, and upper, lower, left andright side surfaces in a state that a TCON cover, an inverter cover andan upper frame are removed;

FIG. 31 is a view of the module of the display device from a frontsurface in a state that the upper frame is removed;

FIG. 32 is a perspective view of the module of the display device in astate that the upper frame is removed;

FIG. 33 is a perspective view for explaining the fitting relationship ofthe upper frame, an intermediate frame and a lower frame;

FIG. 34 is a perspective view for explaining the fitting relationship ofthe upper frame, the intermediate frame and the lower frame;

FIG. 35A to FIG. 35E are views for explaining the fitting relationshipat a portion A in FIG. 34 in more detail;

FIG. 36A and FIG. 366B are views for explaining the positioning at aportion B in FIG. 34 in more detail;

FIG. 37 is an exploded perspective view showing the parts constitutionof the intermediate frame;

FIG. 38A and FIG. 38B are a front view and an side view of the vicinityof a drain printed circuit board in a state that the upper frame isremoved;

FIG. 39A to FIG. 39C are a front view and side views of one cornerportion of the module in a state that the upper frame is removed;

FIG. 40 is a view for explaining the holding structure of a cable;

FIG. 41A and FIG. 41B are explanatory views of a divided drain printedcircuit board;

FIG. 42A to FIG. 42D are explanatory views showing the schematiccross-sectional structure of the module of the display device;

FIG. 43A to FIG. 43C are explanatory views of a fixing method of a coverof a display device;

FIG. 44A to FIG. 44D are views showing a constitutional example of abacklight portion;

FIG. 45 is an explanatory view of the arrangement positions of commonspacers;

FIG. 46 is a view for explaining a schematic example of a system of thedisplay device:

FIG. 47 is an explanatory view showing an example of predeterminedvalues of a data set;

FIG. 48 is an explanatory view showing an example of the relationshipbetween the data set and the gray scale-brightness characteristics;

FIG. 49 is an explanatory view of rising sequences of a driver powersource and a gray scale reference power source;

FIG. 50A to FIG. 50F are explanatory views showing various screendisplay examples in an information display mode;

FIG. 51A and FIG. 51B are explanatory views showing an example of atechnique for changing over to the information display mode;

FIG. 52 is an explanatory view showing the connection of a displayelement CEL, a tape carrier TCP and a printed circuit board PCB;

FIG. 53A to FIG. 53C are explanatory views on the measurement of theconnection resistance between the tape carrier TCP and a printed circuitboard PCB;

FIG. 54A and FIG. 54B are explanatory view on the measurement of theconnection resistance between the tape carrier TCP and the displayelement CEL;

FIG. 55A and FIG. 55B are explanatory view on the measurement of theconnection resistance between the tape carriers TCP and the displayelement CEL by way of a plurality of tape carriers TCP;

FIG. 56A and FIG. 56B are schematic connection views of the printedcircuit board PCB, the tape carrier TCP and the display element CEL in astate that a connection resistance measurement pattern is incorporated;

FIG. 57A to FIG. 57C are explanatory views of an example of themeasurement of the connection resistance between the tape carrier TCPand the printed circuit board PCB;

FIG. 58A to FIG. 58C are explanatory views of an example of themeasurement of the connection resistance between the tape carrier TCPand the display element CEL;

FIG. 59 is a system diagram showing the signal transmission between aTCON and a memory;

FIG. 60 is a flow chart of a mode change;

FIG. 61 is an explanatory view of the mode changeover timing;

FIG. 62 is an explanatory view of one example of the detailed structureof the pixel of the display device according to the present invention;

FIG. 63 is an explanatory view of one example of the detailed structureof the pixel of the display device according to the present invention;and

FIG. 64 is an explanatory view of one example of the detailed structureof the pixel of the display device according to the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Embodiments of the present invention are explained hereinafter inconjunction with drawings.

<Overall Schematic Constitution>

A display device according to the present invention includes a displayelement as a constitutional element thereof. FIG. 27 is an explodeperspective view showing one example of the module structure of thedisplay device. The display element CEL is positioned between an upperframe UFM and a lower frame LFM. The upper frame UFM includes an openingportion and a display region DR of the display element CEL is exposedfrom the opening portion so that the display region DR can be observed.As an example, when the display element CEL is a liquid crystal displayelement, a backlight unit BL which becomes a light source of light to betransmitted through the display element CEL is arranged on a backsurface of the liquid crystal display element. An intermediate frame MFMis arranged on a peripheral portion of the backlight unit BL and aperipheral portion of the display element CEL is positioned on theintermediate frame MFM thus determining the position of the displayelement CEL. In the display device, a controller TCON which generatesvarious signals for realizing an image display on the display elementCEL is provided.

FIG. 26 is a system schematic diagram showing a path for generating adisplay signal to the display element CEL in response to a signal fromthe controller TCON. Signals from the outside of the display device, forexample, a signal from a TV set, a signal from a PC and other variouscontrol signals are inputted to the controller TCON as an externaloutput OI. The controller TCON forms such signals into signals to besupplied to the display element CEL for an image display. The signalsdiffer depending on the display element CEL. For example, the variouscontrol signals are formed into desired signal depending on cases suchas a case in which the display element CEL is a liquid crystal displaydevice, a case in which the display element CEL is an EL display device,a case in which the display element CEL is a FED display device. Toconsider the case in which the display element CEL is the liquid crystaldisplay device as an example, the controller TCON supplies a videosignal line drive circuit signal DS to a video signal line drive circuitDD and supplies a gate signal line drive circuit signal GS to a gatesignal line drive circuit GD. Various voltages Vd for video signal linedrive circuit which include a drive voltage for circuit per se and aplurality of gray scale reference voltages are supplied to the videosignal line drive circuit DD from a power source circuit PS, whilevarious voltages Vg for gate signal line drive circuit which include adrive voltage for the gate signal line drive circuit per se and areference voltage which becomes the reference with respect to the gatevoltage are supplied to the gate signal line drive circuit GD from thepower source circuit PS. Further, as a common potential of the displayelement CEL, a common potential voltage Vc is supplied. A video signalis supplied to video signal lines DL from the video signal line drivecircuit DD and a gate signal is supplied to gate signal lines GL fromthe gate signal line drive circuit GD, wherein using a switching elementTFT formed on the pixel, in response to the control signal to the gatesignal lines GL, a potential of the video signal line DL is supplied toa pixel electrode PX (described later). By driving the liquid crystalmolecules with an electric field or a voltage difference between thepixel electrode PX and the common potential Vc, the state of the liquidcrystal layer is changed so as to realize the image display.

<Display Element>

<<Example of Arrangement of Group of Pixels>>

One example of a group of pixels of the display element CEL is shown inFIG. 1. The video signal of the video signal line DL is supplied to thepixel electrode PX by way of the switching element TFT which iscontrolled by the gate signal lines GL. The common potential is suppliedto the common electrode CT via the common signal line CL. The electricfield is generated between the pixel electrode PX and the commonelectrode CT and hence, the liquid crystal layer is driven whereby thedisplay is performed.

The constitutional feature of the constitution shown in FIG. 1 lies inthat the extending direction of the electrodes differs among the upper,lower, left and right pixels which are arranged close to each other.Accordingly, this embodiment is characterized in the arrangement per sethat the extending direction of the electrodes differs among the upper,lower, left and right pixels. One example of the division of pixelpattern for realizing such a constitutional feature is shown in FIG. 2.Symbol UE indicates an upper electrode which constitutes an upper layerand includes a large number of line-like portions or slits. Symbol LEindicates a lower electrode which constitutes a lower layer and isformed in a planar shape. Depending on the direction of the slits, forexample, of the upper electrode UE, the extending direction of theelectrode can be changed and hence, the direction of the electric fieldcan be controlled.

FIG. 2A shows a pixel pattern in which the slits extend in the rightupward direction, while FIG. 2B shows a pixel pattern in which the slitsextend in the right downward direction. By alternately arranging thesetwo pixel patterns as the neighboring pixels in the upper, lower, leftand right directions, it is possible to realize the constitution inwhich the extending direction of the electrodes differs among the upper,lower, left and right pixels. So long as the extending direction of theelectrodes differs among the upper, lower, left and right pixels, anypixel structure can be used. For example, the present invention mayapply to the arrangement of the direction of the slits or projections ina vertical orientation method (a VA method) display device.

FIG. 3 shows one example of color filter arrangement in the arrange ofthe group of pixels in FIG. 1. As the color filters, the color filtersof three primary colors consisting of red (R), green (G) and blue (B)are arranged, for example. In these three primary colors, the colorfilters in common color are arranged in the group of pixels in thelongitudinal direction. Due to such an arrangement, as can be clearlyunderstood from FIG. 2, even when the pixels are observed in view ofeach monochroic unit, the extending direction of the electrodes differsamong the upper, lower, left and right pixels. It is more desirable thatthe extending directions of the electrodes are arranged in symmetrybetween the neighboring pixels with respect to the extending directionof the video signal line GL or the extending direction of the gatesignal line GL. Due to such a constitution, it is possible to realizethe improvement of a viewing angle not only in the case of white displaywhich performs the display using all of R, G, B but also in the case ofprimary color display which performs the display using only one colorout of R, G, B. This implies that it is possible to realize theimprovement of the viewing angle even in the display of the color otherthan white which is realized by combining a plurality of colors.

An advantageous effect on the improvement of the viewing angle obtainedby such a constitution is explained in conjunction with FIG. 4. FIG. 4is a view which shows the arrangement shown in FIG. 3 in an expandedmanner. Symbols (A), (B) respectively correspond to, for example, thepixel (a) and the pixel (b) in FIG. 2. That is, these pixels are pixelswhich differ in the extending direction of the electrodes. Symbols R, G,B in the drawing indicate the correspondence with the display of thecolors R, G, B.

For example, in performing the white display, the display is performedusing all pixels. Accordingly, the pixels (B) are uniformly arrangedoutside the G(B) of the pixel (A). Accordingly, it is possible to offsetthe viewing angle dependency (or the directional dependency of coloring)of the pixels (A) and the viewing angle dependency of the pixels (B) andhence, the viewing angle dependency can be reduced. Particularly, whenthe electrode arrangement direction of the pixels (A) and the electrodearrangement direction of the pixels (B) are arranged in symmetry withrespect to the gate signal line GL or the video signal line DL, it ispossible to maximize the offset effect and hence, it is possible torealize the wide viewing angle which substantially eliminates theviewing angle dependency.

Next, the case in which the red (R) display is performed is considered.With respect to the pixel R(B) in the drawing, the pixels of R which arearranged closest in the upper, lower, left and right direction of thepixel R(B) are always constituted of the pixels R(A). Further, withrespect to the pixel R(A) in the drawing, the pixels of R which arearranged closest in the upper, lower, left and right direction of thepixel R(A) are always constituted of the pixels R(B). That is, itbecomes apparent that since only the pixels of R are used in themonochroic display of red, it is possible to improve the viewing anglealso in the monochroic display of red in the same manner as the whitedisplay. In the same manner, the improvement of the viewing angle isrealized also in the monochroic display of B meaning blue and in themonochroic display of G meaning green.

Further, since the colors other than the monochroic colors can bedisplayed as the combinations of R, G, B, it is possible to realize theimprovement of viewing angle in the display of these colors. That is, itis possible to achieve the remarkable advantageous effect that thedisplay device having the wide viewing angle can be realizedirrespective of the kinds of colors.

Such a wide viewing angle is particularly preferable in the displaydevice applicable to a large-sized TV set. Further, in the large-sizedTV set which has been developed for digital broadcasting, an aspectratio (for example, 16:9) of a screen is larger than an aspect ratio(4:3) of a conventional NTSC type TV set and hence, it is possible toensure a large perspective angle from a viewer at the center and cornerportions of a screen. Accordingly, this technique is extremely effectivefor realizing the enlargement of the viewing angle due to thearrangement of the group of pixels set forth in the concept of thepresent invention.

Further, compared to a case in which a plurality of electrode directionsare provided in the inside of the single pixel, it is possible to unifythe arrangement direction of electrodes in the inside of one pixel andhence, invalid regions and domain generating regions can be reducedwhereby the enhancement of numerical aperture can be realized and, atthe same time, the enhancement of brightness and the reduction of powerconsumption of the display device as a whole can be realized. Further,since a pattern in the inside of the pixel can be simplified, forexample, the flow of an etching solution in performing the wet etchingof fine line-like or slit-like electrodes in the inside of the pixel isunified whereby defects on etching such as the formation of residues orthe disconnection can be reduced thus capable of enhancing a yield rate.

<<Arrangement Example of Polarization Transmission Axis and InitialOrientation Direction>>

When the above-mentioned liquid crystal display element is used as thedisplay element CEL, to eventually convert the modulation of light bythe liquid crystal layer to a visible state, in the transmissive-typeliquid crystal display element, for example, the liquid crystal layer isarranged between two polarizers. In the liquid crystal layer, theorientation of the liquid crystal is changed by the electric fieldgenerated by the above-mentioned electrodes, for example. In a statethat the voltage is not applied to the liquid crystal molecules of theliquid crystal layer, as an example, the treatment which aligns theliquid crystal molecules in one direction is performed. This treatmentis called as the initial orientation treatment and the initialorientation direction ORI is set by the orientation treatment whichapplies rubbing to the orientation film or irradiates polarizationultraviolet rays to the orientation film.

One example of the relationship between the polarization transmissionaxis of the polarizer and the initial orientation direction in the pixelhaving the line-like or slit-like pattern shown in FIG. 2 is shown inFIG. 8A and FIG. 8B. Symbol GL indicates the extending direction of thegate line, symbols PL1, PL2 indicate polarization transmission axes ofone and another polarizers and these polarization transmission axes PL1,PL2 are arranged to be orthogonal from each other. The initialorientation direction ORI is arranged as shown in FIG. 8A when theliquid crystal molecules have the positive dielectric anisotropy and isarranged as shown in FIG. 8B when the liquid crystal molecules have thenegative dielectric anisotropy. Accordingly, when the electric field isgenerated between the pixel electrode PX and the common electrode CT, itis possible to make the direction of rotation of the liquid crystalmolecules opposite from each other between the pixel shown in FIG. 2Aand the pixel shown in FIG. 2B whereby it is possible to constitute thedisplay element CEL having the wide viewing angle irrespective of thecolor displayed when the above-mentioned arrangement is combined withthe arrangement shown in any one of FIG. 1 and FIG. 3 to FIG. 7.Further, in a display mode in which the initial orientation directionbecomes substantially perpendicular to the substrate, that is, in aso-called vertical orientation method, the initial orientation directionORI becomes the perpendicular direction. In this case, the arrangementis configured such that the directions that the liquid crystal moleculesare inclined assume a plurality of directions when the voltage isapplied to the liquid crystal. However, also in this case, it isdesirable that two polarizers are arranged to become orthogonal fromeach other to realize the high contrast and the wide viewing angle.

<<Supply Example of Common Voltage to Group of Pixels>>

In supplying the common voltage to the group of pixels, as shown in FIG.1 as one example, it is possible to supply the common voltage to thegroup of pixels which extend in the lateral direction, for example,using the common signal line CL. However, as can be clearly understoodfrom FIG. 1, the common signal lines CL are spaced apart from eachother. By making the common potential more stable, it is possible tomake the display quality stable. Further, it is also possible to reducea line width of the common signal line CL thus realizing the furtherenhancement of the numerical aperture.

FIG. 5 shows an example in which the common electrodes CT of the pixelswhich are arranged close to each other in the vertical direction areelectrically connected with each other using a bridge line BR. Since thecommon electrodes CT of the respective pixels are connected to thecommon signal line CL, the common potential is supplied to therespective pixels from the upper, lower, left and right directions in amatrix array whereby the common potential can be largely stabilized.

FIG. 6A shows an example in which each bridge line BR is provided for aplurality of pixels. In the drawing, one bridge line BR is allocated tothree pixels. The common potential stabilization effect obtained by thebridge line BR has the feature that the brightness irregularitiesbetween the neighboring rows can be eliminated compared to the casewhich has no bridge line. This feature can be achieved by electricallyconnecting the neighboring common signal lines CL which extend inparallel. Since the connection distance is short and the frequency islarge, it is unnecessary to make the bridge line BR have the lowresistance comparable to the resistance of the common signal line CL.Accordingly, even when the bridge lines BR are arranged in a state thatone bridge line BR is allocated to the plurality of pixels, it ispossible to obtain the advantageous effect.

By arranging the bridge line BR in a state that one bridge line BR isallocated to the plurality of pixels, there exist the pixels which haveno bridge line BR and, in these pixels, a space over the gate signalline GL becomes wider than the pixel having the bridge line BR.Accordingly, it is preferable to form the pixels as shown in FIG. 6Bwhere support columns SOC or the like which hold the distance betweentwo substrates of the display element CEL are arranged in the pixels.

FIG. 7 shows an example in which the pixels on which the bridge line BRis arranged are not aligned in a straight line in the longitudinaldirection. Since the bridge line BR is arranged close to the videosignal line DL, a parasitic capacitance is generated between the bridgeline BR and the video signal line DL. When the bridge lines BR areuniformly provided to all pixels, the generation of the parasiticcapacitance also becomes uniform and hence, there is no influence of theparasitic capacitance to the image quality. However, when the bridgelines BR are provided only to the group of pixels which extend in theparticular longitudinal direction, the parasitic capacitance isgenerated only on the group of pixels and hence, there arises thedifference in the parasitic capacitances of video signal lines DL.Although it is possible to design the bridge lines BR such that noinfluence of a level which causes a drawback in view of image quality isgenerated, it is needless to say that it is desirable to eliminate sucha possibility in principle. Accordingly, by arranging the bridge linesBR as shown in FIG. 7, the generation of the parasitic capacitance isdiffused so as to eliminate the possibility of the influence to theimage quality.

<<Detailed Example of Pixel>>

FIG. 9 shows one example of the detailed structure of the pixel which ispreferably used in the display element CEL. Hereinafter, a large numberof features which this pixel possesses are explained sequentially.

<<TFT Portion>>

Features of the TFT portion shown in FIG. 9 are explained. The videosignal line DL is connected with the drain electrode D of the switchingelement TFT. The drain electrode D is formed in a shape which surroundsthe source electrode S in a semicircular manner. Further, there isprovided a semiconductor layer a-Si which has an end portion thereofarranged further outside the drain electrode D and is formed in asemicircular shape. By controlling the turning ON/OFF of thesemiconductor layer a-Si by the gate signal line GL, theconduction/interruption between the drain electrode D and the sourceelectrode S can be controlled. By forming the drain electrode D in asemicircular shape which surrounds the source electrode S, it ispossible to increase a channel width thus improving the writingcharacteristics of the TFT. Further, by also forming a distal endportion of the source electrode S into a semicircular shape, it ispossible to prevent the channel length from becoming non-uniform and, atthe same time, it is possible to prevent the deterioration of thereliability attributed to the concentration of electric field.

The video signal line DL is connected with the drain electrode D using aconnecting member which is integrally formed with the drain electrode D.In connecting the video signal line DL, the connecting member has alarge width at a connecting portion thereof with the video signal lineDL and a narrow width at a connecting portion thereof with the drainelectrode D. Further, a hole is formed in the gate signal line GL in thevicinity of the connecting portion and the video signal line DL isconfigured not to be overlapped with the gate signal line GL in thevicinity of the connecting portion. Due to such a constitution, it ispossible to achieve the prevention of the disconnection of theconnecting portion and the reduction of the crossing capacitance wherebythe parasitic capacitance of the video signal line DL can be reduced.Further, since the connecting member gets over the gate signal line GLwith an angle, that is, since the connecting member gets over the gatesignal line GL in a non-perpendicular manner, the possibility ofdisconnection can be reduced.

<<<Pixel Electrode Connecting Portion>>>

The source electrode S of the switching element TFT in the pixel shownin FIG. 9 once gets over the gate signal line GL and extends and,thereafter, is bent in the direction parallel to the gate signal line GLand, subsequently, is bent and extends in the direction of the gatesignal line GL and forms a connecting region. The gate signal line GL isformed in a state that the gate signal line GL is recessed in theconnecting region portion, that is, in a state that a line width thereofis narrowed thus ensuring the connecting region. The source electrode Sand the pixel electrode PX are electrically connected with each othervia a through hole TH1 formed in the connecting region. The reason thatthe connecting region is arranged in a state that the connecting regionintrudes toward the gate signal line GL side is to ensure the numericalaperture. Further, the resistance of the line becomes dominant at anarrowest portion of the line. In the constitution shown in FIG. 9, thegate signal line GL has a hole at an intersecting portion thereof withthe video signal line DL and is formed into two portions which have anarrow line width and these two portions are merged again to form thebold line. This branching of the gate signal line GL into two portionsis, when the short-circuiting is generated between the gate signal lineGL and the video signal line DL, to enable the correction of theshort-circuiting by separating the branched portion where theshort-circuiting is generated. Since the total line width of the gatesignal line GL is narrow at this portion, with respect to the resistanceof the gate signal line GL, the value becomes dominant at the portionhaving this width. Accordingly, by forming the connecting portion withthe pixel electrode PX in a state that the connecting portion intrudestoward the gate signal line GL side, the enhancement of numeral apertureis realized and, at the same time, the substantial increase of theresistance value of the gate signal line GL attributed to the intrusionof the connecting portion can be restricted to a trivial value. Further,the gate signal line GL is configured to have a large width at theportion where the TFT is formed than the portion where the gate signalline GL crosses the video signal line DL or the vicinity of theconnecting portion with the pixel electrode PX. Accordingly, it ispossible to ensure the large channel width of the TFT and hence, thedisplay device which exhibits the high yield rate and the high imagequality can be realized.

<<<Common Signal Line and Common Electrode>>>

In the pixel shown in FIG. 9, the common signal line CL extends inparallel with the gate signal line GL. The common signal line CL isformed of a metal material on the same layer as the gate signal line GLas an example. The common signal line CL is connected with the commonelectrode CT. Here, in the application of the present invention to areflective-type display device, for example, the common electrode CT maybe formed integrally with the common signal line CL using the samematerial. However, when the common electrode CT adopts the planarconstitution as shown in FIG. 9, to use the display element CEL in thetransmission display, it is necessary to use the common electrode CTformed of a transparent electrode. Accordingly, the electricalconnection between the common electrode CT and the common signal line CLis constituted as the connection of different layers. Since the commonelectrode CT and the common signal line CL constitute the differentlayers, in performing the connection, there arises a phenomenon that onelayer gets over another layer and a disconnection may occur at theget-over portion. Accordingly, the prevention of such a disconnectionbecomes important for ensuring a yield rate.

FIG. 12A and FIG. 12B show an example of a case in which the commonsignal line CL is formed above the common electrode CT and the commonsignal line CL directly gets over the common electrode CT. In theconstitution shown in FIG. 12B, when the common signal line CL gets overthe common electrode CT, the get-over portions OH are formed on bothsides of the common electrode CT. These get-over portions OH areextremely thin having the same width with the common signal line CL ascan be understood from the drawing. When the disconnection occurs alsoon either one of these get-over portions OH, the common electrode CTcause a line defect. Accordingly, this example provides the structurewhich largely influences the yield rate.

FIG. 12A shows the improved structure, wherein end portions or end sidesof the common electrode CT are arranged to fall within the width of thecommon signal line CL. In other words, the common electrode CT isarranged such that the end portions thereof are arrange to be positionedin the midst of the common signal line CL in the widthwise direction.Accordingly, it is possible to ensure a region where the common signalline CL extends without being overlapped to the common electrode CT andhence, it is possible to set the possibility of occurrence of completedisconnection at an extremely low level. Further, it is possible toprolong an extension length of the end sides of the common electrode CTon the common signal line CL and hence, even when the disconnectionoccurs by a chance, it is possible to supply the common potential to thecommon electrode CT from the common signal line CL through otherportion. Accordingly, it is possible to ensure the highly reliableconnection having redundancy and hence, the high-quality display devicecan be realized with a high yield rate.

<<<Connection of Common Potential of Upper and Lower Pixels>>>

By electrically connecting the common potentials of the neighboringupper and lower pixels, the common potentials are made stable. In FIG.9, the electrical connection is established using the bridge line BR.

In FIG. 9, the common signal line CL includes a projecting portion or alarge-width portion at a portion thereof. This portion constitutes acommon potential connecting portion CC of upper and lower pixels towhich the common potential is supplied from the common signal line CL.The bridge line BR is connected to the common potential connectingportion CC via a through hole TH2. The bridge line BR is arranged overthe gate signal line GL in a spaced-apart manner by way of at least thegate insulation film GI, traverses the gate signal line GL and extendsto another neighboring pixel. In another pixels which are arranged closeto the pixel in the vertical direction, a different island-like commonpotential connecting portion CC is formed. The common potentialconnecting portion CC is formed of the same metal as the common signalline CL, for example, and has at least a portion thereof overlapped tothe common electrode CT. The bridge line BR is connected with thisisland-like common potential connecting portion CC by way of the throughhole TH2. Accordingly, it is possible to establish the electricconnection of the common potentials of the neighboring pixels in thevertical direction.

The different island-like common potential connecting portion CC may, inthe structure which forms the common signal line CL on the portion, beintegrally formed with the common signal line CL. However, by supplyingthe matrix-like common potentials using the bride line BR, a demand forthe line resistance of the common signal line CL is reduced and hence,by forming the common signal line CL only on one end side of the pixel,it is possible to increase the numerical aperture correspondingly.

Further, even when the bridge line BR is directly connected to thecommon electrode CT without through the common potential connectingportion CC, it is possible to achieve the matrix power supply withrespect to the electrical connection. However, to take the yield rateand the image quality into consideration, it is more preferable toestablish the electric connection via the common potential connectingportion CC.

That is, since the connection is performed via the through hole, a layerthickness of the liquid crystal layer differs in the vicinity of thethrough hole and hence, there may be formed a region where leaking oflight occurs due to a reason that the orientation treatment is notperformed sufficiently whereby the image quality is liable to be easilylowered. Accordingly, by forming the common potential connecting portionCC using a metal material which generally possesses the light blockingproperty, it is possible to achieve the light blocking of the throughhole portion. It is needless to say that, in the reflective-typestructure or the like in which the common electrode CT is made of ametal material, the common electrode CT also serves as the commonpotential connecting portion CC.

Further, the connection at the common potential connecting portion CC isestablished by connecting the bridge line BR to the through hole. Thatis, the bridge line BR is patterned by etching. When the display deviceis normally manufactured, the material and the connection structure ofthe bridge line BR and the common electrode CT do not influence theyield rate. However, in performing the patterning by exposing the bridgeline BR, there exists a step in which a photo resist is formed in a sameshape as the bridge line BR, the etching is performed using the photoresist as a mask, and an extra portion around the bridge line BR isremoved. Since the bridge line BR is formed as an isolated thin pattern,the bridge line BR is formed in a pattern with which the photo resistwhich constitutes a mask during etching is extremely easily peeled off.Further, when the photo resist is peeled off, the bridge line BR of thethrough hole portion is removed by etching and, at the same time, thelines and the electrodes arranged below the through hole portion aredirectly exposed to the etching. Here, assuming that the lines orpattern below the through hole portion are made of the same material asthe bridge line BR, the pattern below the through hole portion areetched. When the bridge line BR is made of the same material such asITO, SnO or the like as the transparent electrode or the commonpotential connecting portion CC as an example, the transparent electrodeof the common potential connecting portion CC is remarkably etched inthe horizontal direction thus arising the possibility that a defectoccurs in an image display region in the inside of the pixel. Assumingthat the common signal line CL is also made of the same material, thisdefect may lead to the disconnection of the common signal line CL. Thisbecomes a cause of lowering the yield rate. Accordingly, by providingthe common potential connecting portion CC which is made of the materialdifferent from the material of the bridge line BR, even when a defectoccurs by a chance during the step for forming the bridge line BR, it ispossible to obviate the occurrence of the display defect of the pixel.This is because that when the defect occurs only on the bridge line BR,so long as one connection is allocated to the plurality of pixels, it isstill possible to maintain the bridge connection effect and hence, it ispossible to obtain only the image quality improvement effect attributedto the bridge line BR.

Further, by arranging the common electrode CT such that the commonelectrode CT is brought into contact with the lower portion of thecommon potential connecting portion CC, even when the common electrodeCT and the bridge line BR are made of the same type of material, it ispossible to provide a protective region at the time of etching using thecommon potential connecting portion CC made of different material in awide range whereby the possibility of deteriorating the yield rate canbe fundamentally eliminated.

Further, the bridge line BR traverses the gate signal line GL and hence,the bridge line BR forms the parasitic capacitance with gate signal lineGL. To reduce this parasitic capacitance, it is desirable to use aconductive layer remotest from the gate signal line GL as the bridgeline BR.

In total, it is desirable that the bridge line BR is formed of thetransparent electrode made of a material such as ITO, SnO, ITZO, IZO,ZnO or the like formed on the protective film PAS and the commonpotential connecting portion CC is made of the same metal material asthe common signal line CL.

Further, in the example shown in FIG. 9, the common electrode CT isconstituted of a planar electrode and is formed of a transparentelectrode made of a material such as ITO, SnO, ITZO, IZO, ZnO or thelike. Accordingly, it is desirable that the common electrode CT isconnected to the common potential connecting portion CC from below thecommon potential connecting portion CC. Here, when both of the commonelectrode CT and the bridge line BR are formed of the transparentelectrode, it is preferable to use the same transparent electrodematerial such as ITO, for example, from a viewpoint of the common use ofa film forming device and an etching device in the manufacturing steps.

Further, in the constitution shown in FIG. 9, the pixel electrode PX ispositioned above the common electrode CT and includes a large number offine line-like-like portions or slit-like portions. When the displayelement is used as the element for transmissive display, it is alsopreferable that the pixel electrode PX is also formed of the sametransparent electrode material. By forming the pixel electrode PX on thesame layer as the bridge line BR, it is possible to obviate the increaseof the number of layers of the layer structure and hence, the number ofsteps can be obviated.

In FIG. 9, one end of the pixel electrode PX is arranged to beoverlapped to the common potential connecting portion CC. In the commonpotential connecting portion CC, the bridge line BR to which the commonpotential is applied is formed on the same layer as the pixel electrodePX and constitutes a singular point in the display device which performsthe display using the electric field generated between the potential ofthe pixel electrode PX and the common potential. Since the direction ofthe electric field differs from the originally intended direction, thisbecomes a cause of the deterioration of the image quality. Accordingly,by overlapping this region on the common potential connecting portion CChaving the light blocking property, the influence is eliminated.Further, for that end, a shape of an end side of the common potentialconnecting portion CC and a shape of an end side of the pixel electrodePX have the similar shapes in a region where the common potentialconnecting portion CC and the pixel electrode PX are overlapped to eachother.

Here, the common potential connecting portion CC is formed in a shapewhere the pixel-electrode-PX-side corner portions thereof are cut. Thisprovision is made to eliminate the undesired light blocking region thusenhancing the numerical aperture. In this case, as shown in FIG. 9, thepixel electrode PX and the common potential connecting portion CC areconfigured to be overlapped to each other at three sides which areunparallel to each other and the pixel electrode PX and the commonpotential connecting portion CC, that is, the light blocking layersextend in parallel.

Here, by forming the vicinity of the connecting portion of the bridgeline BR in the same manner, it is possible to minimize the requiredlight blocking region.

In this region, the distance between the pixel electrode PX and thebridge line BR as viewed in parallel is set longer than the distancebetween the bridge line BR and the common electrode CT as viewed inparallel. This provision is made to obviate the short-circuitingattributed to the constitution that the pixel electrode PX and thebridge line BR are formed on the same layer and, at the same time, tosufficiently ensure the contact surface area between the commonelectrode CT and the common potential connecting portion CC.

<<<Arrangement of Group of Pixels>>>

The pixel electrode PX shown in FIG. 9 is configured such that a largenumber of slits extend in one direction and the direction differs amongthe pixels which are arranged close to each other in the upper, lower,left and right directions. Due to such a constitution, it is possible toenlarge the viewing angle irrespective of the kind of color. Here, thisarrangement of the group of pixels relates to the viewing angleenlarging effect and even with respect to a case in which a plurality ofdirections exist in the inside of one pixel or a case in which the samedirection is given in all pixels, these cases can obtain otheradvantageous effects attributed to other disclosed constitutions.

Further, the color filters CF are, as an example, are arranged suchthat, as shown in FIG. 3, wherein the color filters CF are common in thelongitudinal direction and the color filters of colors R, G, B arearranged in the lateral direction. In arranging the color filters CF, itis desirable to form the black matrix BM as a partition between thecolor filters CF and a light blocking layer for enhancing a contrastratio due to the light shielding of undesired regions. FIG. 10 shows anexample of a case in which a black matrix BM is formed with respect to apattern shown in FIG. 9. The black matrix BM is formed in principle suchthat the end portions of the black matrix BM falls within the inside ofthe region where the pixel electrode PX is formed. However, since thecommon potential connecting portion CC functions as a light blockinglayer in the portion of the common potential connecting portion CC, itmay be possible to form a boundary in a region which exceeds the pixelelectrode PX.

<<<Cross-Sectional Structure>>>

The cross-sectional structure of an essential part of the pixel shown inFIG. 9 or FIG. 10 is sequentially explained.

FIG. 11 shows the cross-sectional structure of a A-A′ portion shown inFIG. 9 or FIG. 10. On the first substrate SUB1, the common electrode CTis formed as the lowermost layer. As an example, the common electrode CTis formed of a transparent electrode, for example, made of ITO. The gatesignal line GL and the common signal line CL are made of metal. The gatesignal line GL extends between the regions where the common electrode CTis formed. The common signal line CL has a portion thereof formed in astate that the portion gets over the common electrode CT and suppliesthe common potential to the common electrode CT. Further, since commonsignal line CL is arranged such that the whole thereof does not get overthe common electrode CT, the disconnection of the common signal line CLis obviated. The gate insulation film GI is formed in a state that thegate insulation film GI covers the common electrode CT, the commonsignal line CL and the gate signal line GL. On the gate insulation filmGI, a metal layer S which is extended from the source electrode S of theswitching element TFT is arranged and this extended portion constitutesa connecting portion with the pixel electrode PX. For this end, the gatesignal line GL on the A-A′ cross section has a small line width. Theprotective film PAS is formed on the source electrode S. The pixelelectrode PX is formed of the transparent electrode, for example, ITO inthe same manner as the common electrode and is arranged on theprotective film PAS. The pixel electrode PX and the source electrode Sare connected with each other via the through hole TH1 formed in theprotective film PAS, while the video signal which is supplied from thevideo signal line DL is supplied to the pixel electrode PX through theswitching element TFT. The orientation film AL is formed on the pixelelectrode PX and the initial orientation treatment is applied to theorientation film AL on demand. On a back surface of the substrate SUB1,the first polarizer PL1 is formed.

The second substrate SUB2 is arranged to face the first substrate SUB1in an opposed manner. Black matrixes BM which block the undesiredleaking of light are formed on the second substrate SUB2. Color filtersCF are formed in a state that end portions thereof are overlapped to theblack matrixes BM. Although two color filters CF are shown in a spacedapart manner in the drawing, since the color of the color filters CF inthe A-A′ cross-sectional direction is equal, the color filters CF may beintegrally formed. The overcoat film OC is formed in a state that theovercoat film OC covers the color filters CF and the black matrixes BM.An orientation film AL is formed on the overcoat film OC. On a backsurface side of the second substrate SUB2, the second polarizer PL2 isformed. A conductive layer such as ITO may be formed between the secondsubstrate SUB2 and the second polarizer PL2 on demand. This is becausethat such a constitution brings about an advantageous effect of blockinga leaked electric field and of reducing EMI. Further, it is alsopossible to prevent the undesired static electricity from influencingthe display of the liquid crystal layer.

The liquid crystal layer LC is formed between the substrate SUB1 and thesubstrate SUB2. An electric field is generated by applying a voltagedifference between the pixel electrode PX and the common electrode CTand the orientation of the liquid crystal molecules of the liquidcrystal layer LC is changed from the initial orientation direction bythe electric field thus controlling the visible display image.

The initial orientation direction ORI imparted by the orientation filmsAL of the substrate SUB1 and the substrate SUB2 is parallel to thesubstrate SUB1 and the substrate SUB2, wherein the relationship whichthe initial orientation direction ORI makes with the polarizationtransmission axes of the polarizers PL1, PL2 assumes the relationshipwhich is explained in conjunction with FIG. 8 as one example. Due tosuch a constitution, it is possible to realize the normally blackcharacteristics in which the display exhibits black when the voltage isnot applied and the brightness is increased along with the applying ofthe voltage.

FIG. 13 is the cross-sectional structure taken along a line B-B′ in FIG.9 or FIG. 10. On the protective film PAS, the bridge line BR which isformed of the transparent electrode, for example, ITO is formed on thesame layer as the pixel electrode PX. The bridge line BR electricallyconnects the common electrodes CT of the pixels arranged close to eachother in the upper and lower directions. The pixel which corresponds tothe lower pixel shown in FIG. 9 or FIG. 10 corresponds to the left-sidepixel region in FIG. 13. The common potential connecting portion CC inthe region is overlapped to the common electrode CT from above thecommon electrode CT and is electrically connected with the commonelectrode CT. The common potential connecting portion CC is formed ofthe same metal layer as the gate signal line GL. The common potentialconnecting portion CC is connected with the bridge line BR via thethrough hole TH2. Here, the bridge line BR and the common electrode CTare not directly connected with each other and the common potentialconnecting portion CC made of the metal material is interposed betweenthem thus realizing the enhancement of the above-mentioned yield rate.The bridge line BR traverses the gate signal line GL by way of the gateinsulation film GI and the protective film PAS. By making thesetraversing lines spaced apart from each other as much as possible, it ispossible to suppress the parasitic capacitance. The bridge line BR whichtraverses the gate signal line GL is connected with another commonpotential connecting portion CC via the through hole TH3. The commonpotential connecting portion CC is integrally formed with the commonsignal line CL. Further, by connecting the common electrode CT as thelower layer, the electric connection between the pixels is established.

FIG. 14 is the cross-sectional structure taken along a line C-C′ in FIG.9 or FIG. 10. This drawing particularly relates to the explanation ofthe structure of the switching element TFT portion. In the region, theblocking of light of the switching element TFT is necessary and hence,the black matrixes BM which constitute the light blocking layer areformed over the whole region of the substrate SUB2. The gate signallines GL formed on the substrate SUB1 are, since hole portions areformed in the gate signal lines GL to perform the above-mentionedcorrection, arranged in a spaced apart manner in FIG. 14. Although thevideo signal line DL extends in the hole portion, to reduce thepossibility of disconnection of the video signal line DL at the time ofgetting over the gate signal line GL before and after the hole portion,the semiconductor layer a-Si is formed below the video signal line DL.The connecting portion extends toward the gate signal line GL from thevideo signal line DL and is connected to the drain electrode D of theswitching element TFT. The source electrode S is sandwiched by the drainelectrodes D from both sides and the semiconductor layer a-Si is formedbetween these two drain electrodes D thus forming the channel region ofthe switching element TFT. Here, usually, a high-concentration dopedlayer n⁺ is formed on an upper surface of the semiconductor layer,wherein the high-concentration doped layer n⁺ remains between the drainelectrode D, the source electrode S and the semiconductor layer a-Si andis removed in the channel region between the drain electrode D and thesource electrode S thus enhancing the characteristics of the switchingelement TFT. However, the constitution is omitted from the drawing.

FIG. 15 is the cross-sectional structure taken along a line D-D′ in FIG.9 or FIG. 10. The black matrix BM is arranged between the pixels whichare arranged close to each other in the lateral direction thusinterrupting the undesired leaking of light. The color filters CF whichare arranged close to each other in the lateral direction differ incolor from each other and hence, the color filters CF exhibit thedifferent colors from each other. In each pixel, the common electrode CTis formed in a planar shape and is formed of the transparent electrodesuch as ITO, for example, in case of the transmissive-type displayelement. When the common electrode CT is used for the reflective-typedisplay element, the metal layer is used as the common electrode CT. Thepixel electrode PX is formed on the protective film PAS and is formed ofthe transparent electrode such as ITO, for example, in case of thedisplay element for transmissive display. Since the pixel electrode PXis directly formed below the orientation film, even in the displayelement CEL for reflective-type display, the pixel electrode PX ispreferably made of the transparent electrode from a viewpoint ofenhancing the reliability.

The pixel electrode PX includes a large number of line-like portions,wherein portions between the line-like portions form regions whichexpose the common electrode CT between the pixel electrodes PX.Accordingly, a route which terminates the electric field from the pixelelectrode PX at the common electrode CT is formed and, by driving theliquid crystal molecules of the liquid crystal layer LC by the electricfield, the image display can be achieved. When both of the pixelelectrode PX and the common electrode CT are formed of the transparentelectrode for transmissive display, the substantially whole displayregion becomes transparent and hence, it is possible to realize thehighly bright display device which exhibits the high opticaltransmissivity.

Further, since the directions of the electrodes can be controlled by thedirections of the line-like portions or the slit portions formed in theupper electrodes such as the pixel electrodes PX, even when the gatesignal lines GL and the video signal lines DL are arranged orthogonally,it is possible to freely set the directions of the electrodes withouthardly influencing the numerical aperture.

<<Another Example of Detailed Example of Pixel>>

In FIG. 9, one example of the detailed structure of the pixel which ispreferably applicable to the display element CEL is shown. Theconstitution and the advantageous effects explained in <<<TFTportion>>>, the constitution and the advantageous effects explained in<<<pixel electrode connecting portion>>>, the constitution and theadvantageous effects explained in <<<common signal line and commonelectrode>>>, and the constitution and the advantageous effectsexplained in <<<Connection of common potentials of upper and lowerpixels>>> can be obtained by pixels having other various planarconstitutions. One example of these pixels is explained.

FIG. 62 is a view which corresponds to FIG. 9 and shows the planarconstitution of the pixel. The largest point which makes theconstitution shown in FIG. 62 different from the constitution shown inFIG. 9 lies in that the arrangement of slits formed in the pixelelectrode PX is common with respect to respective pixels. In FIG. 62,the direction of the slits in the pixel electrodes PX differs between anupper region of the pixel and a lower region of the pixel. That is, theslits are arranged downwardly as the slits extend toward one sidesurface of the pixel in the upper region, while the slits are arrangedupwardly as the slits extend toward one side surface of the pixel in thelower region. That is, the slits are arranged in the direction that theslits are converged to the center of the pixel. Due to such aconstitution, the correction of the viewing angle can be performed inthe inside of one pixel.

Different from the constitution shown in FIG. 9, in the constitutionshown in FIG. 62, there exist regions where the directions of the slitsdiffers, that is, the upper region and the lower region in the inside ofone pixel and hence, the use efficiency of the pixel is lowered at thecenter region which constitutes a boundary between two regions.Accordingly, the numerical aperture is slightly reduced. However, in thedisplay device which is used as a screen of a PC monitor or theInternet, there may be a case that the constitution shown in FIG. 62which always realizes the correction of the viewing angle with respectto any images is suitable. It is possible to select either one of theabove-mentioned constitution shown in FIG. 62 and the constitution whichmaximizes the brightness in FIG. 9 and is particularly suitable fordisplay of natural scene such as the TV set depending on the usage orapplication and there may be a case that the constitution shown in FIG.62 is suitable. In this case, in the image of the PC monitor or theInternet, there is no continuity in the information which is observed inthe natural scene between the pixels and hence, the importance of thenecessity of stability of the common potential between the pixels isfurther increased compared to the case of the constitution shown in FIG.9. Even in such a case, in the constitution where the direction of theslits formed in the pixel electrode PX differs between the upper regionand the lower region of the pixel, by providing the bridge line BR so asto connect the common electrodes CT between the upper and lowerneighboring pixels, it is possible to make the common potential stablethus realizing the stable image display.

Further, when the bridge line BR is formed in the constitution where thedirection of the slits formed in the pixel electrodes PX differs betweenthe upper region and the lower region of the pixel PX, the manner ofarranging the bridge line BR gives the different influence to thenumerical aperture. In FIG. 62, to enhance the numerical aperture, thebridge line BR is formed on a side where the slits are converged.Further, the common potential connecting portions CC are providedrespectively corresponding to upper and lower end portions of the sidewhere the slits are converged. Due to such a constitution, it ispossible to enhance the numerical aperture compared to the case in whichthe common potential connecting portions CC are formed on the side wherethe slits are diffused.

Further, in the constitution shown in FIG. 62, as an example, in thecenter region of the pixel electrode PX, a pattern in which the pixelelectrode PX repeats the expansion and the contraction of a widththereof at least three times is formed. Due to such a constitution, itis possible to provide the constitution whose boundary between the upperregion and the lower region of the pixel electrode PX can be hardlyobserved with eyes and hence it is possible to enhance the integrity ofthe pixel. Further, in the center region of the pixel electrode PX, thepattern in which the pixel electrode PX repeats the expansion and thecontraction of the width at least three times is suitable for avoidingthe rapid change of the potential of the pixel electrode PX. Thisconstitution is particularly effective in the display image or thedisplay method which requires the transitional characteristics ofdisplay, for example, a case in which the black image is written in thescreen periodically.

FIG. 63 is a view which corresponds to FIG. 10 and shows one example ofthe planar structure of the pixel in a state that the light blockinglayer BM is formed on the constitution shown in FIG. 62.

FIG. 64 shows an example which slightly differs from the constitutionshown in FIG. 62 with respect to the constitution of the center portionof the pixel.

In FIG. 64, the slits formed in the pixel electrode PX are formed suchthat the upward slits and the downward slits are alternately meshed witheach other at the center region of the pixel. In FIG. 64, thisconstitution also simultaneously adopts the above-mentioned pattern inwhich the pixel electrode PX repeats the expansion and the contractionof a width thereof at least three times. By adopting the constitution inwhich the upward slits and the downward slits formed in the pixelelectrodes PX are alternately meshed with each other at the centerregion of the pixel, it is possible to enhance the utilizationefficiency of the pixel at the center region whereby the brightness canbe enhanced.

<<Dummy Pixel Region>>

<<<Arrangement of Pixels at Corner Portions>>>

As shown in FIG. 16A a dummy pixel region DMY is arranged in theperiphery of the display region DR of the display element CEL. Thisprovision is made to approximate the conditions such as parasiticcapacitance and the like of the pixel at an outermost periphery of thedisplay region and other pixels as close as possible.

Here, the dummy pixel region DMY can be divided into a plurality ofregions as shown in FIG. 16B. That is, the dummy pixel region DMY can bedivided into an upper dummy pixel region D(D), a lower dummy pixelregion L(D), a left dummy pixel region D(G) and a right dummy pixelregion D(LD). By repeating a pattern which is equal to a pattern in theinside the display regions in these dummy pixels, it is possible toarrange the conditions between the dummy pixel region and the displayregion. Further, from a viewpoint of neutralizing the influence withrespect to any display, it is possible to adopt the structure whichexposes only the common potential. This is because that even withrespect to the pixels used for display, at the time of performing theblack display, the common potential is applied to both of the pixelelectrode PX and the common electrode CT.

Here, with respect to the group of pixels on the outermost periphery ofthe display region which are arranged in parallel in the lateraldirection, for example, with respect to the group of pixels on theoutermost periphery which are arranged in parallel in D (LD) in FIG.16B, the degree of influence from the D(DL) is substantially equalbetween the neighboring pixels. Further, with respect to the group ofpixels on the outermost periphery of the display region which arearranged in parallel in the longitudinal direction, for example, withrespect to the group of pixels on the outermost periphery which arearranged in parallel in D (G) in FIG. 16B, the degree of influence fromthe D(G) is substantially equal between the neighboring pixels. However,with respect to the dummy pixel C1 at the corner portion whichconstitutes a position where the D (LD) and the D (G) intersect impartsthe influence singularly to the pixel at the corner portion of theeffective display region DR which is closest to the C1. Here, since thebrightness change which is singularly generated at the characteristicportion such as the pixel of the corner portion may bring about thepossibility that all products have the defects in common among productsand hence, it is necessary to eliminate such possibility.

Accordingly, the present invention adopts the constitution which allowsthe directions of the electrodes of the pixels at the corner portions tohardly receive the influence from the dummy pixels at the closest cornerportions.

FIG. 17 is a schematic explanatory view and schematically shows thearrangement of the electrodes of the pixel at corner portions in theinside of the effective display region DR which is closest to the dummypixels C1, C2, C3, C4 at the four corner portions of the dummy pixelregion DMY. This arrangement is characterized in that the respectivepixels at the corner portions of the display region adopt the electrodearrangement which hardly receives the influence of the electric fieldfrom the dummy pixels at the corner portions.

This constitution is explained more easily in conjunction with FIG. 18.FIG. 18A shows that the dummy pixels C1, C2, C3, C4 are formed on thecorner portions of the display region DR by taking the center of thedisplay region DR into consideration. Here considered is a case in whichin the group of pixels in the effective display region, groups of pixelshaving two electrode directions shown in FIG. 188B and FIG. 18C whichcorrespond to FIG. 2A and FIG. 2B are present. Here considered is a linesegment which connects C1 and C2 in FIG. 18A, that is, an imaginarydirection of the electric field extending toward the effective displayregion from the dummy pixel and the influence of the electric field withthe electrode shape shown in FIG. 188B and FIG. 18C using a dotted line.In case of the direction of slits shown in FIG. 18B, an acute angle θ1which the dotted line and the slits make is set smaller than an angle θ2which the dotted line and the slits make in case of the direction ofslits shown in FIG. 18C. In case of the direction of slits shown in FIG.18B, the opening portions of the slits are arranged to approach thedummy pixels and hence, the arrangement is liable to easily receive theinfluence of the electric field from the dummy pixel. To the contrary,In case of the direction of slits shown in FIG. 18C, the arrangement isliable to hardly receive the influence of the electric field from thedummy pixel. Accordingly, it is desirable that the pixels at the cornerportions corresponding to C1, C3 have the electrode pattern shown inFIG. 18C. To the contrary, the pixel shown in FIG. 18B is desirable asthe pixels in the vicinity of C2 and C4.

Here, as shown in FIG. 18B and FIG. 18C, the explanation has been madewith respect to the case in which the lower electrode LE whichconstitutes the lower layer is formed in a planar shape and the upperelectrode UE which constitutes the upper layer is formed in a slitshape. However, the same goes for a vertical orientation method in whichonly the upper electrodes UE are formed on one substrate provided thatthe slits are formed.

Although the relationship may be inverted depending on the voltage andthe shape of the dummy pixels at the corner portions, the presentinvention returns to FIG. 17 and the desirable constitution is requiredto satisfy the following (1).

(1) The dummy pixels include the line-like electrodes or slits, whereinthe direction of the line-like electrodes or slits is equal between thepixels formed on the corner portions which face in an opposed manner andat least in the vicinities of the corner portions. It is more preferablethat the following (2) is satisfied in addition to the above-mentioned(1).

(2) The dummy pixels include the line-like electrodes or slits, whereinthe direction of the line-like electrodes or slits differs between thepixels which are most spaced apart from each other on the same side orat least in the vicinities of the corner portions.

To define the above-mentioned arrangement in view of the object, it issafe to say that the electrode arrangement of the pixels in respectivecorner portions of the effective display region assumes the arrangementwhich suppresses the influence from the dummy pixels at the cornerportions.

To define the dummy pixels with respect to the case corresponding to theexplanation of FIG. 18, the definition becomes as follows (3).

(3) When two kinds of pixels which differ in the direction of theline-like electrodes or the slits are provided, it is safe to say thatwith respect to the direction of the linear electrodes or slits formedin the pixels at the corner portions, by comparing an acute intersectingangle which the direction of the line-like electrodes or the slits makeswith respect to a line which connects the corner portion and the centerof the display region, the pixels having the direction of the slits orthe electrodes which intersects with an angle larger than the acuteintersecting angle are arranged.

<<<Supply of Common Potential Using Dummy Pixel Region>>>

FIG. 19 is a view for explaining the supply of the common potentialusing the dummy pixel region in the vicinity of the corner portion andshows the region in the vicinity of the C1 shown in FIG. 16 or FIG. 17.

Below the pixel on the display region at the lowermost side, a dummygate line DMYG is arranged, wherein the dummy pixels are arranged suchthat the conditions thereof approximate the conditions of other pixels.Below the dummy gate line DMYG, the dummy pixel region, that is, thedummy pixel region which corresponds to the D(LD) in FIG. 16 or FIG. 17extends. The structure of the dummy pixel region D (LD) is explained inconjunction with FIG. 20A which show the cross-sectional structure takenalong a line A-A′ in FIG. 19.

A dummy common signal line DMYC to which the common potential issupplied on the same layer with the common signal line CL extends with alarge width. Due to this constitution, a bus line for supplying thecommon potential of low resistance is formed. The gate insulation filmGI is formed on the dummy common signal line DMYC and the video signalline DL extends on the gate insulation film GI. The protective film PASis formed in a state that the protective film PAS covers the videosignal line DL. A PAS hole HL is formed in the protective film PAS andthe gate insulation film GI in a region between the video signal linesDL. An upper shield electrode US is integrally formed with the bridgeline BR using a transparent electrode in a state that the upper shieldelectrode US covers the PAS hole HL. Due to such a constitution, inrespective pixels in the dummy region, the reference potential appearson the uppermost layer and hence, the potential is made stable. Further,the common potential is supplied to the respective pixels in thelongitudinal direction from the dummy common potential line DMYC whichfunctions as the bus line of low resistance via the bridge line BR andhence, the reduction of the power supply resistance of the commonpotential can be achieved.

The dummy common potential line DMYC and the dummy gate signal line DMYGare connected with each other on a left side in FIG. 19 thus obviatingthe change of the potential of the dummy gate signal line DMYG.

Outside the group of outermost peripheral pixels in the longitudinaldirection on the left end, the dummy pixel region extends along the D(G)in FIG. 16 or FIG. 17. In each dummy pixel, an end portion of the commonsignal line CL forms a large width portion. Further, the commonpotential connecting metal line CMC is arranged close to the commonsignal line CL and an end portion of the common potential connectingmetal line CMC also has a large width. These large-width portions arearranged close to each other and are electrically connected with eachother by an upper shield electrode US. The explanation is made inconjunction with FIG. 20B which is a cross-sectional view of a B-B′ lineportion shown in FIG. 19. On the substrate SUB1, the large width portionformed on the end portion of the common signal line CL is formed belowthe gate insulation film GI. The large-width portion of the commonpotential connecting metal line CMC is formed on the gate insulationfilm GI in a state that the common potential connecting metal line CMCis arranged close to the common signal line CL. At these large-widthportions, the PAS hole HL is formed in the gate insulation film GI andthe upper shield electrode US is formed in a state that the upper shieldelectrode US covers the hole portion whereby the common potentialconnecting metal line CMC and the common signal line CL becomeelectrically conductive with each other. Further, the upper commonconnecting line UC is electrically connected with the DMYC throughanother hole portion thus realizing the supply of the common potentialto the DMYC.

The common potential connecting metal line CMC and the gate signal lineGL are formed on the different layers. This is because that the commonpotential is supplied to the common potential connecting metal line CMCusing the gate signal line GL toward the display region from the outsideon the left side in FIG. 19 and hence, a large number of these lines arearranged in a closely arranged manner corresponding to the number of thepixels whereby the common potential connecting metal line CMC and thegate signal line GL are formed on the different layers by way of thegate insulation film GI for obviating the short-circuiting and theelectrolytic corrosion.

Also in the vicinities of other C3, C3, C4, in the dummy pixel portion,the lower metal dummy electrode layer and the upper shield electrode USare connected with each other via the PAS hole HL and hence, the commonpotential is exposed whereby the potential of the dummy pixel region ismade stable.

<<<Dummy Pattern>>>

The dummy pixel region DMY is suitable for arranging the dummy patternfor various purposes. Particularly, dummy pixel region DMY is suitablefor arranging a pattern to perform a quality control. FIG. 21 ischaracterized by arranging a plurality of measuring dummy patternsTEG-A, TEG-B, TEG-C on the dummy pixel region DMY. These measuring dummypatterns may be scattered to different sides, or may be concentrated onone side, or may be formed respectively on a plurality of sides. Theimportant point is that the measuring dummy patterns are arranged in thedummy pixel region which is arranged closest to the pixel.

The explanation is made with respect to a case in which the dummypattern adopts a pattern which measures film thicknesses of the gateinsulation film GI, the semiconductor layer a-Si, the protective filmPAS and the like.

The insulation film and the semiconductor layer are formed by a CVDmethod. Accordingly, film thicknesses of the films which are formed byperipheral patterns receive the influence. The purpose of measuring thefilm thickness using the dummy patterns is to know the film thicknesseswithin the display region and, for example, to feedback the obtainedinformation to the film forming conditions in the manufacturing steps.Accordingly, even when the dummy patterns are arranged remote from thedisplay region and obtain the information on different film thicknesses,the information has no values. Accordingly, it is important to arrangethe dummy patterns on the dummy pixel region which is arranged closestto the pixel.

FIG. 22 shows an example in which, for example, one measuring dummypattern TEG is formed in the dummy region shown in FIG. 19. When aplurality of measuring dummy patterns TEG are arranged in the dummyregion, the measuring dummy patterns TEG may be arranged on the separatedummy pixel in the dummy pixel region arranged closest to the pixelbased on the same technical concept which is explained hereinafter.

In the dummy pixel where the measuring dummy pattern TEG is arranged, asize of the PAS hole HL formed in the protection film PAS is reduced.Then, on the region which is covered with the obtained protective filmPAS, the measuring dummy pattern TEG is arranged.

The structure and the manner of using of the measuring dummy pattern TEGrelated to the measurement of various film thicknesses are explainedwith respect to examples of various measuring dummy patterns TEG usingthe cross-sectional structure taken along a line A-A′ in FIG. 22.

FIG. 23A and FIG. 23B show the cross-sectional structure taken along theline A-A′ in FIG. 22, wherein FIG. 23A shows the cross-sectionalstructure at the time of completion and FIG. 23B shows thecross-sectional structure at the time of measuring. The measuring dummypattern TEG-A aims at the measurement of the film thickness of the gateinsulation film GI. In a stage after the formation of the gateinsulation film GI and prior to the formation of the protective filmPAS, as shown in FIG. 23B, a film thickness of the gate insulation filmGI is detected by an optical technique which uses light Light. Since thecommon signal line CL is a metal layer and hence reflects light, it ispossible to know the film thickness of the gate insulation film GI whichis a transparent film using an ellipsometer. In FIG. 23A which shows thecross-sectional structure in the completed form, the region of themeasuring dummy pattern TEG-A is recognized as the dummy pixel havingthe small hole in the protective film PAS.

FIG. 24A and FIG. 24B show the cross-sectional structure taken along theline A-A′ in FIG. 22, wherein FIG. 24A shows the cross-sectionalstructure at the time of completion and FIG. 24B shows thecross-sectional structure at the time of measuring. The measuring dummypattern TEG-B aims at the measurement of the total film thickness of thegate insulation film GI and the semiconductor layer a-Si. In a stageafter the formation of the gate insulation film GI and the formation ofthe semiconductor layer a-Si and prior to the formation of theprotective film PAS, as shown in FIG. 24B, the total film thickness ofthe gate insulation film GI and the semiconductor layer a-Si is detectedby an optical technique which uses light Light. By measuring the filmthickness of the gate insulation film GI alone using the technique shownin FIG. 23, it is also possible to know the film thickness of thesemiconductor layer a-Si alone by the subtraction. In FIG. 24A whichshows the cross-sectional structure in the completed form, the region ofthe measuring dummy pattern TEG-B is recognized as the dummy pixel inwhich the isolated a-Si pattern remains.

FIG. 25A and FIG. 25B show the cross-sectional structure taken along theline A-A′ in FIG. 22, wherein FIG. 25A shows the cross-sectionalstructure at the time of completion and FIG. 25B shows thecross-sectional structure at the time of measuring. The measuring dummypattern TEG-C aims at the measurement of the film thickness of theprotective film PAS. The dummy video pattern DDL constituted of thevideo signal lines DL is formed on the gate insulation film GI. On thedummy video pattern DDL, the protective film PAS is formed. By formingthe dummy video pattern DDL using a metal layer which is formed on thesame layer as the video signal line DL, it is possible to opticallymeasure the film thickness of the protective film PAS using theellipsometer as shown in FIG. 25B.

Further, by performing the measurement after forming the upper shieldelectrode US using the transparent electrode as shown in FIG. 25A, it ispossible to know the film thickness of the transparent electrode bysubtracting the film thickness of the protective film PAS found in thestep shown in FIG. 25B.

In FIG. 25A which shows the cross-sectional structure in the completedform, the region of the measuring dummy pattern TEG-C is recognized asthe dummy pixel in which the pattern which is formed on the same layeras the isolated video signal line DL remains.

<Module Structure>

An example of the module structure shown as the example in FIG. 27 isexplained in more detail.

<<Schematic Structure>>

FIG. 28A is a front view of the display device in a state that the upperframe UFM is mounted. The upper frame UFM is formed of a metal material.An example of a connecting portion ULC between the upper frame UFM andthe lower frame LFM is formed on each side. Further, holes ofpositioning portions PDP are observed.

FIG. 28B, FIG. 28C, FIG. 28D and FIG. 28E are respectively viewscorresponding to a lower surface, an upper surface, a left surface and aright surface of the structure shown in FIG. 28A. The upper frame UFM isformed in a state that the upper frame UFM is bent and extended to sidesurface of respective sides thereof.

Although the upper and lower frame connecting portion ULC are notobserved in FIG. 28B and FIG. 28C, portions of the frame connectingportions ULC are observed in FIG. 28D and FIG. 28E. This structure isadopted to contract a profile size of portions other than the displayregion of the display device. Accordingly, although the upper framestrength outside the upper and lower frame connecting portions ULCbecomes weaker at a short side than a long side of the upper frame,since the distance per se of the frame is short with respect to theshort side and hence, the influence on the rigidity as a whole can besuppressed. Accordingly, it is possible to achieve both of thecontraction of the profile size and the maintenance of the strength.

Further, to maintain the connection strength, the larger number of theupper and lower frame connecting portions ULC are formed on the longside than the short side.

FIG. 29 is a view showing the display device as viewed from a backsurface. Corresponding to the upper and lower frame connecting portionsULC when the upper and lower frame connecting portions ULC are viewedfrom the upper frame, the upper and lower frame connecting portions ULCare also formed on the lower frame LFM.

On the left side of the drawing, an inverter cover (high voltage side)INCH is provided and an inverter printed circuit board (high voltageside) is arranged below the inverter cover INCH. The leaking electricfield from the inverter is shielded by the inverter cover (high voltageside) INCH. On the upper side of the drawing, the controller (printedcircuit board) and a cover of the TCON (TCON cover) TCV are arranged. Onthe right side of the drawing, an inverter cover (low voltage side) INCLis provided and an inverter printed circuit board (low voltage side) isarranged below the inverter cover INCL. The leaking electric field fromthe low-voltage-side inverter printed circuit board is shielded by theinverter cover (low voltage side) INCL.

Both of the inverter cover (high voltage side) INCH and the TCON coverTCV are formed of metal for shielding and a large number of holes areformed in the inverter cover (high voltage side) INCH and the TCON coverTCV for heat radiation. The holes formed in the TCON cover TCV are setsmaller than the holes formed in the inverter cover (high voltage side)INCH. With respect to the frequency of the leaking electric field, thefrequency of the leaking electric field from the controller printedcircuit board is higher than the leaking electric field from theinverter printed circuit board and hence, the heat radiation is achievedwhile preventing the leaking of the electric field from the holes bysetting the holes formed in the TCON cover TCV small. On the other hand,although the frequency from the inverter printed circuit board isrelatively small, an electric current is supplied to the light sourceCFL and hence, the heat generation is large. Accordingly, by forming theholes larger than the holes formed in the TCON cover TCV, it is possibleto obtain both of the heat radiation and the shielding of the leakingelectric field. Further, by changing the sizes of these holes, theresonance frequency of the metal shield plate can be dispersed andhence, the generation of the resonance sounds can be prevented under anyoperation conditions.

FIG. 30A to FIG. 30E are views for showing a state in which therespective covers consisting of the inverter cover (high voltage side)INCH, the inverter cover (low voltage side) INCL and the TCON cover TCVare removed, wherein FIG. 30A is a view as viewed from the back surfaceside.

On the left side of the drawing, an inverter printed circuit board (highvoltage side) INPH is formed. A large number of inverter transformersare arranged on the inverter printed circuit board (high voltage side)INPH. Further, a high-voltage-side output is supplied to the lightsource through a connector.

On the right side of the drawing, an inverter printed circuit board (lowvoltage side) INPL is formed. A low-voltage-side end portion of thelight source is arranged on a connector of the inverter printed circuitboard (low voltage side) INPL. The inverter printed circuit board (lowvoltage side) INPL is divided in two and the divided inverter printedcircuit boards are arranged as the inverter printed circuit board (lowvoltage side) INPL1 and the inverter printed circuit board (low voltageside) INPL2.

The inverter printed circuit board (low voltage side) INPL and theinverter printed circuit board (high voltage side) INPH are connectedwith each other using an inverter printed circuit board connection cableINCC. Due to such a constitution, the low-voltage-side of the lightsource is connected to the connector of the inverter printed circuitboard connection cable INCC via a line on the inverter printed circuitboard (high voltage side) INPH using a connector and the inverterprinted circuit board connection cable INCC is connected with theinverter printed circuit board (high voltage side) INPH using aconnector whereby the supply of electricity to the low voltage sidebecomes possible.

On the lower frame LFM, inverter printed circuit board common connectingportions CCFI which allow the connection of the inverter printed circuitboard to the lower frame LFM are formed. The inverter printed circuitboard common connecting portions CCFI are formed on the lower frame LFMin the left-and-right symmetry. That is, even when the inverter printedcircuit board (high voltage side) INPH and the inverter printed circuitboard (low voltage side) INPL are arranged in a reverse manner in theleft and right direction, it is possible to cope with the situationusing the same display device. This implies that since the heatgeneration from the inverter printed circuit board is relatively large,by adjusting the arrangement relationship with other heat generatingparts within a set of a liquid crystal TV set or the like, the heatgeneration can be made uniform whereby it is possible to prevent thegeneration of locally high-temperature portions.

Since the inverter printed circuit board (low voltage side) INPL can bemade smaller than the inverter printed circuit board (high voltage side)INPH, an extra portion is formed at either side of the inverter printedcircuit board common connecting portion CCFI. Accordingly, in theinverter printed circuit board (high voltage side) INPH, the inverterprinted circuit board common connecting portion CCFI is fixed to thelower frame LFM using given portions formed on both sides of the printedcircuit board. In the inverter printed circuit board (low voltage side)INPL, the inverter printed circuit board common connecting portion CCFIis fixed to the lower frame LFM using given portions formed on one sideof the printed circuit board. For this end, it is desirable that a widthof the inverter printed circuit board (low voltage side) INPL is ½ orless of a width of the inverter printed circuit board (high voltageside) INPH. It is more desirable that a width of the inverter printedcircuit board (low voltage side) INPL is ⅓ or less of a width of theinverter printed circuit board (high voltage side) INPH. This provisionis made to ensure the sufficient fixing strength by the fixing of theprinted circuit board to only one side of the lower frame LFM.

On the upper side of the drawing, a controller printed circuit board isarranged. The controller TCON is formed on the controller printedcircuit board. Outputs from the controller TCON are supplied to thedisplay element CEL by a joiner (A) JNA, a joiner (B) JNB and the likevia the connectors CN1.

FIG. 30B, FIG. 30C, FIG. 30D and FIG. 30E are respectively viewscorresponding to a lower surface, an upper surface, a left surface and aright surface of the structure shown in FIG. 30A. FIG. 30C shows that aprinted circuit board PCB which supplies signals to the video signaldrive circuit of the display element CEL is arranged on a side surfaceof the display device. By connecting joiner (A) JNA and a joiner (B) JNBusing the connector CN2, various signals and voltages are supplied tothe drain printed circuit board DPCB and the controller TCON. The drainprinted circuit board DPCB is constituted of a drain printed circuitboard DPCB1 and a drain printed circuit board DPCB2. These printedcircuit boards DPCB1, DPCB2 are explained later.

FIG. 30D and FIG. 30E show a state that a large number of cables fromthe inverter printed circuit board are arranged.

FIG. 31 shows a state in which the upper frame UFM shown in FIG. 28A isremoved. The intermediate frame MFM is arranged and the display elementCEL is stacked on the intermediate frame MFM. On an upper side of thedisplay element CEL, the video signal drive circuit is formed using thetape carrier TCP as an example. The video signal drive circuit isconnected with either one of the drain printed circuit boards DPCB1,DPCB2. On the left side of the display element CEL, the gate printedcircuit board GPCB is formed. The gate printed circuit board GPCB isconnected to the display element CEL by the tape carrier TCP.

FIG. 32 is a perspective view focusing on the left upper corner portionshown in FIG. 31. A signal from the drain printed circuit board DPCB isapplied to the DTCP and the video signal is applied to the displayelement CEL. A signal from the gate printed circuit board GPCB isapplied to the GTCP and the gate signal is applied to the displayelement CEL. The drain printed circuit board DPCB and the gate printedcircuit board GPCB are connected with each other by the joiner JNC. Dueto such a constitution, compared to the case in which the gate printedcircuit board GPCB is directly connected from the controller TCON, it ispossible to reduce the distance of the joiner JNC and hence, theconstitution which is resistant to noises can be provided.

<<Fixing of Upper and Lower Frames>>

Next, the explanation is made with respect to the upper and lower frameconnecting portions ULC and positioning portions PDP. FIG. 33 is aperspective view showing an exploded state of the upper frame UFM, theintermediate frame MFM and the lower frame LFM. In the upper and lowerframe connecting portions ULC, the upper frame UFM has projectingportions on a lower side thereof, the lower frame LFM has projectingportions on an upper side thereof, and hole portions are formed in theintermediate frame MFM. With respect to the positioning portions PDP,the intermediate frame MFM has projecting portions which are projectedto the upper frame UFM or the lower frame LFM and hole portions areformed on the projection-side frame. This constitution is explained inmore detail. The upper and lower frame connecting portions ULC whichconstitute an A line portion in FIG. 34 and the positioning portions PDPwhich constitute a B line portion in FIG. 34 in a fitting engagementstate of the display device are respectively explained in conjunctionwith FIG. 35 and FIG. 36.

FIG. 35A is a planar schematic view of the upper and lower frameconnecting portions ULC. Symbol MH indicates hole portions formed in theintermediate frame MFM and symbol SC indicates fixing screws.

FIG. 35B is a cross-sectional view taken along a line B-B′ in FIG. 35A.In the upper and lower frame connecting portions ULC, the upper frameUFM projects downwardly and the lower frame LFM projects upwardly. Theholes MH are formed in the intermediate frame MFM and the upper frameUFM and the lower frame LFM are directly brought into contact with eachother through the holes MH. Due to such a constitution, the upper andlower frames can ensure the direct contact with a large area withrespect to the screw SC. By directly connecting the upper frame UFM andthe lower frame LFM using the screw SC, the firm fixing can be realized.Further, since the upper frame UFM and the lower frame LFM are broughtinto direct contact with each other in a wide area around the screw SC,it is possible to ensure the further fixed connection.

FIG. 35C is a cross-sectional view taken along a C-C′ line portion inFIG. 35A and shows that the upper frame UFM projects downwardly and thelower frame LFM projects upwardly. FIG. 35D is a cross-sectional viewtaken along a D-D′ line portion in FIG. 35A and shows a region in astate that the upper frame UFM and the lower frame LFM are separatedfrom each other. FIG. 35E is a cross-sectional view taken along a E-E′line portion in FIG. 35A and shows that the upper frame UFM is arrangedabove the intermediate frame MFM and the lower frame LFM is arrangedbelow the intermediate frame MFM.

FIG. 36A and FIG. 36B are explanatory views related to the positioningportions PDP, wherein FIG. 36A is a perspective plan view and FIG. 36Bis a cross-sectional view taken along a line B-B′ line portion in FIG.36A. An upper projecting portion UP is integrally formed on theintermediate frame MFM. This upper projecting portion UP can realize thepositioning or the alignment of the upper frame UFM with respect to theintermediate frame MFM together with a hole UH formed in the upper frameUFM. Further, a lower projecting portion LP is integrally formed on theintermediate frame MFM. This lower projecting portion LP can realize thepositioning or the alignment of the lower frame LFM with respect to theintermediate frame MFM together with a hole LH formed in the lower frameLFM.

As shown in FIG. 36A, the hole UH formed in the upper frame UFM and thehole LH formed in the lower frame LFM are formed in positions which aredifferent in plane. This provision is provided to release an undesiredforce or stress which may arise at the time of connecting the upperframe UFM and the lower frame LFM by displacing the positions of thehole UH formed in the upper frame UFM and the hole LH formed in thelower frame LFM thus ensuring the firm connection of the upper frame UFMand the lower frame LFM. Further, it is also possible to obtain anadvantageous effect that a resonance point is also dispersed in theupper frame UFM and the lower frame LFM so that the generation of theresonance sound can be prevented.

<<Intermediate Frame>>

The intermediate frame MFM is formed of a resin-made member. Further, asshown in FIG. 37, the intermediate frame MFM is divided into fourmembers consisting of a right intermediate frame MFMR, a leftintermediate frame MFML, an upper intermediate frame MFMT and a lowerintermediate frame MFMB. These four members are formed independentlyfrom each other. Further, the respective members are individuallyconnected to the lower frame LFM. The direct fixing of the dividedintermediate frames MFM are not performed.

In the large-sized module, it is difficult to manufacture the resinmembers with high accuracy. Further, even when the ideal shape isensured in an initial stage, due to the expansion and the contractionwhich occur due to the temperature change, the shape is displaced from ashape which is intended. This displacement of the shape applies to thedisplay element CEL and becomes a cause of deterioration of the displayquality of the display element CEL. Further, this gives rise togeneration of a stress and deterioration of a vibration-resistantcharacteristic of the module.

Accordingly, by dividing the resin-made intermediate frame MFM in fourand by preventing the divided intermediate frames from being directlyfixed to each other, a size of the intermediate frame MFM per eachmember can be made small whereby the intermediate frame MFM which canminimize the influence of the expansion and the contraction attributedto heat can be manufactured with high accuracy. Further, the respectiveintermediate frames MFM are directly fixed to the metal-made lower frameLFM from the intermediate frame MFM side using the screws. Since thelower frame LFM is made of metal, the lower frame LFM can bemanufactured with accuracy and receives the least change of shapeattributed to the temperature change. Accordingly, it is possible tomaintain the position of the intermediate frame MFM with high accuracy.In the above-mentioned upper and lower frame connecting portions ULC, bydirectly fixing the upper frame UFM to the lower frame LFM through thehole portion formed in the intermediate frame MFM from the upper frameUFM side using the screw, the direct firm fixing between theintermediate frame MFM and the upper frame UFM is not provided. That is,both of the intermediate frame MFM and the upper frame UFM are directlyfixed to the lower frame LFM, the reference of the position can beunified to the lower frame LFM and hence, it is possible to manufacturea module having the firm structure with high accuracy. This structure isthe structure which is extremely suitable for a display device having alarge size such as a large-sized TV set.

Among four-split intermediate frames MFM, both of the intermediate frameMFMT and the intermediate frame MFMU extend in one direction, that is,the longitudinal direction (long-side direction) of the display deviceand are formed to have a relatively large length. On the other hand, theintermediate frame MFML and the intermediate frame MFMR are configuredto have a shape which extends both of the lateral direction (short-sidedirection) and the longitudinal direction of the display device, alength of the portion in the longitudinal direction of the displaydevice is made shorter than a length of the portion of the lateraldirection. Due to such a constitution, the intermediate frame MFMT andthe intermediate frame MFMB can ensure the positional accuracy in thelateral direction of the display element CEL, that is, the positionalaccuracy in the vertical direction of the display element CEL with highaccuracy. Further, the intermediate frame MFML and the intermediateframe MFMR can ensure the positional accuracy in the longitudinaldirection of the display element CEL, that is, the positional accuracyin the horizontal direction of the display element CEL with highaccuracy. In this manner, by clearly separating the directions that thepositional accuracy is realized for every member, it is also possible toensure the accuracy even when the resin-made members are applied to alarge-sized display device and hence, the undesired contraction of theprofile size can be prevented.

Further, the intermediate frame MFML and the intermediate frame MFMRhave portions thereof extended in the longitudinal direction. To enhancethe positional accuracy in the vertical direction, it is desirable thatthe intermediate frame MFML and the intermediate frame MFMR are notbrought into contact with end portions of the substrate of the displayelement CEL. Accordingly, it is desirable that the horizontal distancebetween these two intermediate frames and the end portion of the displayelement CEL at the same height in the vertical direction of thesubstrate is set longer than the horizontal distance between theintermediate frames MFMT and MFMB and the end portion of the displayelement CEL at the same height in the vertical direction of thesubstrate.

The intermediate frames MFM which are arranged close to each other have,as shown in FIG. 33, projecting portions which are displaced from eachother. FIG. 38A is a view of the intermediate frames MFM in an assembledstate as viewed from above. The intermediate frame MFMR and theintermediate frame MFMB have projecting portions thereof in thehorizontal direction meshed with each other. Due to such a constitution,the assembly of the intermediate frame MFM is facilitated. Further, inthe vicinity of the fitting portion, the intermediate frame MFMR and theintermediate frame MFML are respectively individually and directly fixedto the lower frame LFM using the screw SC. Due to such a constitution,the accuracy of end portions of the respective intermediate frames MFMcan be realized. With respect to the respective intermediate frames MFM,by directly fixing the intermediate frames MFM to the lower frame LFMfrom the intermediate frame side at a plurality of portions using thescrews S, the connection can be reinforced and, at the same time, theoperability at the time of assembling the module can be enhanced byunifying the fixing with screws to the fixing from the upper side as inthe case of the screw connection at the upper and lower frame connectingportions ULC. The similar shapes can be observed with respect to thefitting portion of the intermediate frame MFMB and the intermediateframe MFMR shown in FIG. 39A.

The intermediate frame MFM increases a resin thickness thereof only atportions thereof which requires the increase of the thickness andreduces the resin thickness at other portions. Due to such a provision,the intermediate frame MFM becomes light-weighted. The shape of theintermediate frame MFM can be freely set on demand by resin injectionmolding which uses a mold.

<<Transmission of Signals to Drain Printed Circuit Board>>

FIG. 38B is a view which is obtained by observing a lower side surfaceof FIG. 38A.

In FIG. 38B, a drain printed circuit board DPCB1 is arranged. Signalsfrom the drain printed circuit board DPCB1 are supplied to a drivecircuit (driver element) DRV on a tape carrier TCP and video signals aregenerated. The video signals are supplied to a video signal terminal ofthe display element CEL from an output terminal of the tape carrier TCP.A drive circuit may be directly mounted on the display element CEL orthe drive circuit may be directly formed on the display element CELusing the TFT.

The drain printed circuit board DPCB1 is fixed to the lower frame LFMusing screws SC. At the same time, when the GND of the drain printedcircuit board DPCB1 and the lower frame LFM are electrically connectedwith each other by such fixing, the stable GND potential can berealized.

Two joiners are connected to the drain printed circuit board DPCB1 fromthe controller printed circuit board side. The joiner (A) JNA has alarge width and a small number of layers. For example, the joiner (A)JNA is constituted of a joiner having one conductive layer. The joiner(B) JNB has a narrow width and a large number of layers. For example,the joiner (B) JNB is constituted of a joiner having two conductivelayers. The joiner (A) JNA is preferably provided for supplying the grayscale power source or the power source of the video signal drivecircuit. On the other hand, the JNB is preferably provided fortransmitting the various kinds of signals such as clocks or the displaydata because the transmission of the high frequency signal can beperformed by increasing the conductive layers. It is possible to adoptthe best joiner and realize the high performance and low cost byseparating the joiners using the signal voltages and the power sourcevoltages in this manner. Further, it is possible to obviate theinterference of the signals and the power source so that the reductionof the noise at transmitting signals and the stabilization of the powersource can be enhanced.

FIG. 41A shows the relationship between the drain printed circuit boardDPCB1 and the drain printed circuit board DPCB2. Two drain printedcircuit boards DPCB1, DPCB2 are independent from each other, and arerespectively fixed to the lower frame LFM. The drain printed circuitboards DPCB are constituted of printed circuit boards, and hence, in alarge-sized display device, it gives rise to a drawback on thereliability such that the accuracy and the deformation of the printedcircuit board per se become causes of the drawback on the image qualityas they apply the stress to the display element CEL or the stress isapplied to the tape carrier TCP and it becomes a cause of thedisconnection. Compared to the case in which drain printed circuitboards DPCB are formed of one large-sized printed circuit board, such apossibility can be reduced by dividing the drain printed circuit boardDPCB into a plural number of boards. In the structure shown in FIG. 41A,two drain printed circuit boards DPCB are respectively and directlyfixed to the lower frame LFM by the screw SC. Due to such aconstitution, drain printed circuit boards DPCB are maintained in a highaccuracy.

The joiner(A) JNA and the joiner(B) JNB are formed on both of the drainprinted circuit boards DPCB1, DPCB2. Here, both joiners(A) JNA arearranged to be positioned inside both joiners(B) JNB. This is because byallowing the extending distances of JNB containing high frequencysignals such as clocks on the respective drain printed circuit boardsDPCB to coincide with each other, the waveform dullness and theinfluence of noises can be made equal whereby the timing control can befacilitated.

FIG. 41B is a view for showing the state of the display element CELbefore the display element CEL is fixed to the lower frame LFM. Thedrain printed circuit boards DPCB have a width wider than the width ofthe gate printed circuit board GPCB since the drain printed circuitboards DPCB have many kinds of voltages to be transmitted andcomplicated signals. Accordingly, in view of the contraction of aprofile size out of the display region, the drain printed circuit boardsDPCB are bent and arranged to the side surface or the back surface asshown in FIG. 41A, on the other hand, the gate printed circuit boardGPCB can be arranged to one end portion of the display element CELwithout being bent. Here, it is preferable that the drain printedcircuit boards DPCB are bent to the side surface and fixed to the lowerframe, LFM other than the drain printed circuit boards DPCB are bent tothe back surface. This is because the leaked electric field from thedrain printed circuit boards can be sealed on the metal made upper frameUFM which is disposed outside the drain printed circuit boards in anassembled state.

<<Inverter Cable>>

FIG. 39B is a side view obtained by observing the FIG. 39A from thelower side. In the drawing, an inverter (transformer) INV is arranged onthe inverter printed circuit board (on the high voltage side). Theoutput at the high voltage side from the connector CNI is supplied tothe light source by the cable.

FIG. 39C is a side view observed from the right side of FIG. 39A. In thedrawing, the output from the inverter is supplied to the light source bythe cable CABLE. Here, the cables CABLE are arranged in plural numberscorresponding to the number of the light sources and hence, itcontributes to the enhancement of the productivity by surely and easilyperforming the fixing. Further, when the cable CABLE is not fixed, theparasitic capacitances become different for respective cables CABLE andthis difference in parasitic capacitance becomes a cause of thebrightness irregularities for every light source and also becomes acause of the disconnection of the cable per se.

As shown in FIG. 39C, the cable CABLE is fixed to the dedicated holdingportion. The holding portion is shown in FIG. 40. The holding portion isintegrally formed with a side mold SM (described later) and is made ofresin. The cable CABLE from the connector CN is arranged to the regionwhich is surrounded by the side surface of the side mold SM and aholding member HOLD. The movement of the cable CABLE in thefront-to-rear direction is restricted as shown in FIG. 40. Further, thecable CABLE is arranged along the R portion having the circular shapeformed above the holding member HOLD. The cable CABLE is again made toreturn to the lower side from the R portion and is connected with thelight source. Due to such a constitution, the movement of the cableCABLE in the vertical direction in the drawing is restricted.

The fixing is realized by simply fitting the cable into the holdingportion having such a simple constitution.

<<Cross-Sectional Structure of Module as a Whole>>

FIG. 42B is a cross-sectional view taken along a line B-B′ in FIG. 42A.The upper frame UFM is arranged on the display element CEL by way ofspacers SP2. These spacers SP2 are formed of a member having resiliencysuch as rubber, for example. The upper frame UFM extends around thedisplay element CEL and, thereafter, bends along a side surface of thedisplay element CEL. A video signal line driving circuit DD is arrangedon the left side of the drawing. A tape carrier TCP is connected to aterminal of the substance SUB1 of the display element CEL and this tapecarrier TCP is connected to the drain printed circuit board DPCB. Thejoiner FPC is connected to the connector CN1 on the drain printedcircuit board DPCB and the joiner FPC is connected to the connector CN2of the controller TCON (circuit board) and hence the power sourcevoltage and various kinds of signals are supplied to the display elementCEL. An intermediate frame MFM is arranged below the display element CELby way of spacers SP1. The lower frame LFM is arranged below theintermediate frame. The lower frame LFM is formed of an approximatelyplaner plate in a region below the display element CEL and is raisedupwardly at the peripheral portion of the display element CEL and isextended again horizontally to form a contact surface with theintermediate frame MFM. Subsequently, the lower frame LFM is bentdownwardly again to form a fixing portion to which the drain printedcircuit board DPCB is fixed and, at the same time, to ensure therigidity of the module as a whole.

A light source CFL is arranged between the display element CEL and thelower frame LFM. A reflection sheet RS which reflects the light from thelight source is arranged between the light source CFL and the lowerframe LFM. A white plastic sheet, for example, can be used as areflection sheet RS. The reflection sheet RS is bent in the obliquedirection at a peripheral portion thereof and is raised upwardly.Thereafter, the reflection sheet RS is extended horizontally and ispressed by a diffusion plate DFP which is stacked on the reflectionsheet RS. The diffusion plate DFP is, for example, formed of a whileplastic plate and diffuses the light from the light source CFL and so asto make the brightness difference between a region which includes thelight source and a region which does not include a light source uniform.Furthermore, a condensing sheet such as a prism sheet, a diffusion sheetand the like are arranged on demand between the diffusion plate DFP andthe display element CEL.

FIG. 42C is a cross-sectional view taken along a line C-C′ in FIG. 42A.Although FIG. 42A shows the cross-section on the same side as FIG. 42B,FIG. 42C explains a portion at a displaced position. The constitutionalfeature which makes the constitution shown in FIG. 42C different fromthe constitution shown in FIG. 42B lies in that a hole is formed in aportion of the lower frame LFM arranged below the intermediate frame MFMand an end portion of the reflection sheet RS is fitted into the hole.This constitutional feature enables the extremely simple and reliablepositioning of the reflecting sheet.

FIG. 42D is a cross-sectional view taken along a line D-D′ in FIG. 42A.In this direction, it is necessary to pull out many cables from thelight source CFL. Resin-made side molds SM are arranged for thispurpose. Each side mold SM is fitted from the upper side to the lowerframe LFM with screws SC. Here, the principle which uses the lower frameas the reference is also strictly observed thus realizing high accuracy.Here, by sandwiching the end portion of the reflection sheet RS betweenthe lower frame LFM and the side mold SM, the fixing of the reflectionsheet RS is realized simultaneously with the fixing of the side mold SMto the lower frame LFM. On the left side of the drawing, a gate printedcircuit board GPCB which is connected with the display element CEL usingthe tape carrier TCP is described.

FIG. 43A and FIG. 43B are views showing the fixing of the TCON cover TCVwhich shields the controller printed circuit board TCON and the lowerframe LFM. FIG. 43A shows the constitution before fixing and the endportion of TCB is bent towards the side of lower frame LFM. As shown inFIG. 43B, pressing the end portion to the lower frame LFM, the lowerframe LFM and the TCON cover TCV are fixed by screws SC in thiscondition. This fixing brings the TCON cover TCV and the lower frame LFMinto contact with each other and allows both of them to becomeconductive with each other not only at the screws but also at a largearea of the TCON cover TCV whereby it is possible to enhance the effectto shield the electric field leaked from the controller TCON (substrate)by the TCON cover TCV. The existence of this provision can be determinedbased on whether a side which is bent in the direction toward the lowerframe is present on an end portion of the TCON cover TCV or not when theTCON cover TCV is separated by removing the screws SC of the TCON coverTCV and the lower frame LFM.

The similar constitution is applicable to the inverter cover so as tocontribute to the enhancement of the leaked-electric field shieldingeffect.

<Light Source>

When the light source has a plurality of fluorescent tubes, thearrangement example of the fluorescent tubes is shown in FIG. 44A. Inthis manner, in case that a large number of fluorescent tubes arearranged, it is important to achieve the uniformity of the brightness ofthe fluorescent tubes. Since high frequency and high voltage are appliedto the fluorescent tubes, the parasitic capacitance is differentdepending on the distance between the fluorescent tubes and themetal-made lower frames LFM thus giving the influence to the intensityof the brightness. Accordingly, it is important to maintain the distancebetween the fluorescent tubes and the lower frame LFM uniform as much aspossible.

FIG. 44B is a view showing an example of the arrangement of the commonspacer CSP such that the common spacer CSP longitudinally crosses theplurality of fluorescent tubes. As an example, by using rubber as thematerial, the shape can be formed freely and the placing operation canbe made easily. Further, the same members are collectively arranged tothe plurality of light sources, the distance between the fluorescenttubes and the lower frames can be easily set to the value which is morethan the value which is set by the thickness of the common spacer CSP.When the distance between the fluorescent tubes and the lower framebecomes is increased, the degree of influence attributed to thedifference in distance is rapidly lowered so that it is important toprevent the fluorescent tubes from being arranged excessively close tothe lower frame.

By forming the common spacer CSP using the resilient member such asrubber or sponge, it is possible to obtain an advantageous effect thatthe rupture of the light source can be prevented when the vibration andthe impact are applied to the common spacer CSP.

FIG. 44D is a view showing a case that the reflection sheet RS isarranged between the common spacer CSP and the light source. Due to sucha constitution, the uniformity of the brightness in the light source CFLextending direction by the common spacer CSP can be improved.

Although the common spacer CSP can be arranged at an arbitrary position,it is desirable to arrange the common spacer CSP at least at highvoltage when the light source has a high voltage side and a low voltageside. This is because that the fluctuation of the distance between thelight source and the lower frame LFM at a high voltage side has a largerinfluence on the brightness than at the low voltage side. FIG. 4C andFIG. 4D are views showing an example of an arrangement of a commonspacer CSP at least at a high voltage side in a case that when theoutput from the inverter INV has a high voltage side and a low voltageside, the light source CFL is connected from the high voltage side usinga cable CABLE (HV) and the light source CFL is connected from the lowvoltage side using the CABLD (LV).

FIG. 45 is a perspective view of the back surface showing the positionalexample of the arrangement of the common spacer CSP in the actualmodule. FIG. 45 shows the example in which common spacers CSP arecollectively arranged in common with the whole light sources such thatthe common spacers CSP are arranged close to the high voltage side.

<System>

<<γ Characteristics>>

FIG. 46 is a system constitutional example which can change the γcharacteristics indicative of the relationship between the gray scalesand the brightness.

Signals from the outside of the display device such as signals of TV,signals of PC, or other various control signals are inputted to thecontroller CON as the external inputs OI. The controller TCON forms theabove-mentioned signals into the signals for making the display elementsCEL to perform the image display. These signals are different from eachother depending on the display elements CEL and are formed into thesignals necessary for the respective display devices. For example,depending on whether the display element CEL is a liquid crystal displaydevice, an EL display device or a FED display device, the signals areformed into signals necessary for the display device. For example, whenthe display element CEL is the liquid crystal display device, forexample, a video signal line drive circuit signal DS is supplied to thevideo signal line drive circuit DD from the controller TCON, and a gatesignal line drive circuit signal GS is supplied to the gate signal linedrive circuit GD from the controller TCON. Various voltages Vd for avideo signal line drive circuit containing a drive voltage of thecircuit per se and a plurality of gray scale reference voltages aresupplied to a video signal line drive circuit DD from a power sourcecircuit PS. Various voltages Vg for the gate signal line drive circuitwhich include a drive voltage of a gate signal line drive circuit per seand the voltage which becomes the reference with respect to a gatevoltage are supplied to the gate signal line drive circuit GD. Further,a common signal line voltage Vc is supplied as the common potential ofthe display element CEL. The video signal is supplied to the videosignal line DL from the video signal line drive circuit DD and the gatesignal is supplied to the gate signal line GL from the gate signal linedrive circuit GD. The potential of the video signal line DL is suppliedto the pixel electrode PX in response to the control signal of the gatesignal line GL by a switching element TFT provided to the pixel. Bydriving the liquid crystal molecules by the electric field or thevoltage difference between the pixel electrode PX and the commonpotential Vc, the state of the liquid crystal layer is changed and theimage display is realized.

The constitutional feature which makes the constitution shown in FIG. 46different from the constitution shown in FIG. 26 lies in that althoughthe gray scale reference voltage Vref is also generated in the powersource circuit PS in FIG. 26, in FIG. 46, the gray scale referencevoltage Vref is generated in the D/A converter D/A in response to thesignal from the controller TCON. Accordingly, the Vref can be changed inresponse to the signal from the controller TCON. Since the video signalline drive circuit DD generates the voltage for every gray scale inresponse to the Vref, the γ characteristics can be changed by changingthe Vref.

In the example of the system shown in FIG. 46, a memory MEM which cansupply information to the controller TCON is arranged. The memory MEMcan hold the data corresponding to the plurality of γ characteristics asan example. In the table 1, the data corresponding to the three kinds ofγ characteristic is stored in the memory MEM as a set of data A, B, C.It is explained that the actual brightness-gray scale characteristicscan be changed in response to the plurality of γ data in FIG. 47 andFIG. 48. TABLE 1 No. Data Set 1 A 2 B 3 C

In FIG. 47, the example of the case which has temporarily four kinds ofvoltages as the gray scale reference voltage Vref is shown. The voltagevalues are respectively recorded in the memory MEM corresponding to thedata set A, B, C. The controller TCON selects one data set which is usedamong the data sets and generates the actual gray scale referencevoltage Vref corresponding to the data set using the D/A converter D/A.Accordingly, the gray scale-brightness characteristics shown in FIG. 48have a curve corresponding to the gray scale reference voltage data forevery data set. That is, the change of the γ characteristics can berealized.

At the time of supplying the gray scale reference voltage Vref from theD/A converter D/A to the video signal line drive circuit DD, it isdesirable that the gray scale reference voltage is raised at thesequence shown in FIG. 49. In FIG. 49, the axis of abscissas indicatestime, and the axis of ordinates indicates voltage. At the time t1, thepower source voltage Vdv of the video signal line drive circuit ispreliminarily raised and the supply of the gray scale reference voltageVref from the D/A converter D/A is started at the time t3 before thepower source voltage Vdv of the video signal line drive circuit reachesthe stationary state. Then, after the Vdv reaches the stationary stateat the time t2, the gray scale reference voltage Vref is set to thestationary state at the time t4. When the gray scale reference voltageVref is generated by a D/A converter D/A, various kinds of gray scalereference voltages are applied to the video signal line drive circuitDD. This is because that the breakdown or the deterioration ofdielectric strength of the video signal line drive circuit DD can beprevented in such a case.

<<Manufacturing Information Display>>

In a display device in which various settings including the change ofthe γ characteristics are possible, it is important to take measureswith which it is possible to recognize what kind of setting is actuallytaken in the display device. Therefore, in the display device of thepresent invention, the setting information is made displayable. To bemore specific, since the display device includes the display elementsCEL, the information is directly displayed on the display elements CEL.One example of a technique for simply switching the information displaymode and the normal display mode is shown in FIG. 51. An output from oneterminal of the controller TCON is exposed on the controller TCON(substrate) using a first pin. Then, a second pin which is arrangedclose to the first pin and is connected to the GND potential isprepared. As shown in FIG. 51A, in a state that these two pins areopened, TCON performs a normal display. On the other hand, as shown inFIG. 51B, when these two pins are short-circuited using a short bar, thecontroller TCON can recognize the request for the information displaymode and hence, it becomes possible to switch the operation to theinformation display mode.

Various examples of the information display screen are shown in FIG. 50Ato FIG. 50F. FIG. 50A is an example in which data stored in normaltextual information per se is displayed. FIG. 50B shows an example inwhich the version information or the customer information is displayed.Although FIG. 50A and FIG. 50B are directly displayed by letters, toconsider a process control on the manufacturing line, when theinformation is displayed in patterns rather than letters, the controlusing the automatic recognition using a machine becomes easier.Accordingly, FIG. 50C shows an example in which a barcode pattern isdisplayed. In the same manner, as shown in FIG. 50D, a two-dimensionalbar code may be displayed.

Further, when the number of types of the information which areconfigured to be displayed may be small, simply, as shown in FIG. 50E,the information may be displayed by changing the number of strips. Thismethod has an advantageous effect that this display can be easilydiscriminated by both of a machine and a human. Further, when it isdesired to further increase an amount of information, as shown in FIG.50F, in addition to the number of the strips, the color information ofR, G, B may be added. It is possible that the amount of the informationwhich can be displayed is increased to the number of strips×the numberof colors used for the method and, at the same time, it is possible toobtain an advantageous effect that the recognition is furtherfacilitated especially for a human.

<<Changeover of Frequency>>

In a display device, there exists a demand for changing of the frequencyof image display corresponding to the kinds of the image informationwhich are configured to be displayed. As an example, such request may beoccurred at the time of mainly displaying a still image and at the timeof mainly displaying a moving image. In FIG. 59, a constitutionalexample in which the frequency changeover is realized is shown. To theexternal input OI, except for the normal signal to be inputted, a modechange signal is inputted. The controller TCON temporarily stores theimage signal in the inputted signals in the memory MEM. Then, inresponse to the frequency which is set with respect to the operationmode instructed using the mode signal, the image signal is read out fromthe memory MEM and the signal is outputted to the video signal linedrive circuit DD or the like.

In this constitution, there exists a drawback that the mode changesignal is inputted from the outside of the display device. For example,an image process processor in a TV judges the contents of the image andinstructs the operation mode to the display device using the mode changesignal. In this case, the mode change signal is inputted to the displaydevice at the time when the external processing device judges asnecessary. However, when the display frequency of the screen isimmediately switched in response to the mode change signal, there arisesa drawback such that the writing-in frequency is changed from the middleof the screen thus generating an irregular brightness and the irregularbrightness is observed for a moment or excess or deficiency of datawithin the memory occurs thus disturbing the display.

FIG. 60 is a flowchart for resolving this drawback. When the mode changesignal is received by the controller TCON, the controller TCON examinesthe changeover timings of a plurality of display modes which differ inthe frequencies. At this time, when the timings are corresponded witheach other, the mode change is performed and, when the timings are notcorresponded with each other, it is processed such that the mode changeis postponed until the timings are corresponded with each other.

FIG. 61 is a view showing the relationship of the timings at the mode 1and the mode 2 which differ in the frequencies from the image data fromthe outside.

From the outside, the image data is inputted as OI, and this image datais sequentially shown in 1, 2, 3 by a frame unit. This implies that thetime passes as it goes in the right direction in the drawing. This datais temporarily stored in the memory, is sequentially read out from thememory and is displayed. When assuming that the mode 1 is a mode havinga high frequency, the data which are read out from the memory aresequentially displayed as 1, 2, 3, 4. Then, since the frequency is high,the data catches up the input of the image information from the outside.At this time, by using the frame, by operating such as writing in ablack screen on the screen or the like, for example, display of the holdtype display device such as a liquid crystal display device which ismade closer to the display of the impulse type display device can berealized and the display of the moving image can be made in visuallyhigh speed. The mode 2 is a mode displaying a screen with the samefrequency as the input information and is sequentially displayed as 1,2, 3 corresponding to the image information from the outside.

As clearly explained in FIG. 61, the timing in which the mode 1 and themode 2 are corresponded with each other is limited to the timingdescribed as switching timing in the drawing. In the timing rather thanthe switching timing, irregularity is unavoidably generated in thedisplay image for a moment. Therefore, it is necessary to perform theswitching of the display mode at the corresponded timing in theflowchart shown in FIG. 60 or the like and, by this means, for the userwho observes the image, a state in which no image irregularity isoccurred at the time of changing the mode can be realized.

<Measurement of Resistance of the Connecting Portion>

A passage through which a signal of the printed circuit board PCB istransmitted to the display element CEL in the display element CEL isshown in FIG. 52. The signal line SL3 on the printed circuit board PCBis electrically connected with the signal line SL2 on the tape carrierTCP using the connecting portion ACF2. The signal line SL2 and thesignal line SL1 on the display element CEL are electrically connectedusing the connecting portion ACF1. By using this constitution, thesignal is transmitted from the printed circuit board PCB to the displayelement CEL. At this time, it is favorable that the connectionresistance of the connecting portion ACF is measurable using the actualmanufacturing. This is because it is useful for the quality managementduring the manufacturing process. To be more specific, when theconnecting portion is an anisotropic conductive film, since theconnection resistance is easily changed, the necessity for themanagement is increased. Then, means for measuring this connectionresistance with a reliable accuracy using a product or a wiring patternwhich enables the measurement are invented.

FIG. 53A is a schematic view as the base for the following explanations.The connection resistance of the connection portion between the displayelement CEL and the tape carrier TCP is R (TC), the connectionresistance of the connection portion between the tape carrier TCP andthe printed circuit board PCB is R (TP). FIG. 53B shows the arrangementfor enabling the measurement of R (TP) in the manufacturing stage. Acommon potential line bus CSL is arranged to the display element CEL.This implies that the respective tape carrier TCP and the displayelement CEL are connected at two places separately. Respective twoconnections which are separately connected to this common potential linebus CSL and form R (TC) are formed. In one connection out of these twoconnections, the line is divided on the tape carrier TCP thus formingthree R (TP). This implies that the respective tape carrier TCP and theprinted circuit board PCB are connected at three places separately. Theline which is divided on the tape carrier TCP is further divided on theprinted circuit board PCB. In this stage, there are four lines and therespective lines form measurement terminals as A1 to A4 corresponding tothe respective lines on the printed circuit board PCB. Here, as shown inFIG. 53C, by supplying a constant current between A1 and A3 and bymeasuring the voltage difference between A2 and A4, R (TP) is easilycalculated as a voltage/current. This measurement concept per se iswidely known as the four terminal method and as a highly accurateresistance measurement method. The improvement is characterized in that,by designing the wiring arrangement in such a manner that the divisionsare formed on the tape carrier TCP and the printed circuit board PCBusing the method, the measurement is made enable in the actual displaydevice.

FIG. 54A and FIG. 54B are views showing the constitution which enablesthe measurement of the R (TC). As shown in FIG. 54A, three lines areconnected to the common potential line bus CSL and, one out of threelines is divided on TCO and constitutes terminals B1 and A1 to A3. Here,as shown in FIG. 54B, by supplying a constant current between B1 and A2terminals and by measuring the voltage between A1 and A3, R (TC) is alsoeasily calculated as the voltage/current.

FIG. 55A and FIG. 55B are views showing a modified example of theconstitution shown in FIG. 54A and FIG. 54B. The line which is connectedto the B1 terminal is formed by a route which passes through anothertape carrier TCP and, as shown in FIG. 55B, R (TC) can be calculatedusing the same measurement as FIG. 54A.

An arrangement which corresponds to the measurement of both of R (TC)and R (TP) and is favorably adopted for an actual use shown in FIG. 56.The common potential line bus CSL on the display element CEL is alsoused as a bus line for supplying the common potential VC. The respectivetape carriers TCP have driver elements DRV arranged in the centerthereof, the respective driver receives an input signal INPUT from theprinted circuit board PCB and produces a signal used for the display ofthe display element CEL and the signal is supplied to the display regionthrough the signal line SIG. Each tape carrier TCP has a commonpotential supply line which does not pass through the driver element DRVformed on the outside of the driver element DRV. This supply line isconnected to the common potential line bus CSL on the display elementCEL and also connected to the common bus line CB which is formed on theprinted circuit board PCB. Accordingly, when the common potential VC issupplied to the common bus line CB, the common potential is supplied tothe common potential line bus on the display element CEL. This commonpotential supply line has a measurement terminal L4 formed on theprinted circuit board PCB. Further, a measurement line is formed in astate that the measurement line is connected to the common potentialline bus CSL, extends on the tape carrier TCP and is connected on theprinted circuit board PCB, and a measurement terminal L3 is formed onthe printed circuit board PCB. This measurement line is sequentiallydivided on the tape carrier TCP and the printed circuit board PCB thusincreasing the number thereof and each line has a measurement terminalformed on the printed circuit board PCB. Accordingly, the measurementterminals L1 to L4 are formed. On the opposite side of the printedcircuit board PCB by way of the driver element DRV, terminals R1 to R4are formed in a symmetrical manner, for example. When the commonpotential line bus CSL is formed in the region between the neighboringtape carriers TCP as shown in FIG. 56A, the groups of measurementterminals of R1 to R4 and L1 to L4 are completed with respect to theneighboring tape carriers TCP with each other.

Here, it is constituted such that the lines other than the commonpotential supply line are not connected to VC.

FIG. 56B shows an example in which, by setting a plurality of commonpotential supply lines, lowering of the power supply resistance at thepower supplying of the common potential is realized.

FIG. 57A to FIG. 57C are views showing a method in which R (TP) ismeasured using the constitution of the arrangement of FIG. 56A. FIG. 57Ais a measurement example of a case in which the voltage is measured bysupplying a current from a constant current source. FIG. 57B is anexample of a constitution in which a voltage is supplied to the commonbus line, a ammeter is connected to R3 and the point of the ammeter isconnected to the ground. When the voltage configured to be supplied tothe common bus line is other than the ground potential, a current ismeasured thus enabling the calculation of R (TP). In this method, VC canbe directly measured as a normal common potential and hence, there is anadvantageous effect that it is not necessary to prepare the constantcurrent source. Further, there is an advantageous effect that themeasurement of R (TP) can be performed during the operation of thedisplay elements CEL. FIG. 57C is an example of a constitution in which,instead of the constant current source shown in FIG. 57A, the ammeterand the voltage source are used in combination.

FIG. 58A to FIG. 58C are views showing a constitutional example at themeasurement of R (TC). FIG. 58A shows an example in which the constantcurrent source is used and, by connecting the constant current sourcebetween R1 and L3 and measuring the voltage between R2 and L2, R (TC)can be calculated. FIG. 58B shows an example of a case in which thecommon potential VC is supplied and the ammeter is connected to L3 andthe output of the ammeter is grounded. The voltmeter is connectedbetween R2 and L2. FIG. 58C is an example of a constitution in which,instead of the constant current source shown in FIG. 58A, the ammeterand the voltage source are used in combination.

<<Examples of Various Inventions Disclosed in this Specification>>

Examples of various inventions disclosed in this specification aredescribed hereinafter.

<<A: TFT>>

(A-1) A display device in which the display device includes asemiconductor layer on a gate signal line and a drain electrode and asource electrode which are formed on the semiconductor layer and has thedrain electrode connected with a video signal line using a connectingmember at a connecting portion, the improvement being characterized inthat the gate signal line has a hole in the vicinity of the connectingportion, and the connecting member sets a width thereof at theconnecting portion with the video signal line larger than a widththereof at a connecting portion with the drain electrode.

(A-2) A display device being characterized in that, in the constitution(A-1), the drain electrode is formed in a shape which surrounds aperiphery of the source electrode in a semicircular shape.

(A-3) A display device being characterized in that, in the constitution(A-1), the connecting member gets over the gate signal line with anangle.

<<B: Pixel Electrode Connecting Portion>>

(B-1) A display device in which the display device includes asemiconductor layer formed on a gate signal line and a drain electrodeand a source electrode formed on the semiconductor layer, has the drainelectrode connected to a video signal line, and has the source electrodeconnected to a pixel electrode in a connecting region, the improvementbeing characterized in that the source electrode once extends over thegate signal line and, thereafter, is bent in the direction parallel tothe gate signal line and extends, and is subsequently bent in thedirection of the gate signal line thus forming a bent connecting region.

(B-2) A display device being characterized in that, in the constitution(B-1), the gate signal line is formed in a state that the gate signalline is recessed in the connecting region portion.

(B-3) A display device being characterized in that, in the constitution(B-1), the gate signal line is formed in a state that a line widththereof is made fine in the connection region portion.

(B-4) A display device being characterized in that, in any one of theconstitutions (B-1) to (B-3), the gate signal line has a hole at acrossing portion between the gate signal line and a video signal line,the gate signal line is divided into two portions having a fine linewidth, and two portions are merged again to form a bold line.

(B-5) A display device which constitutes a TFT by forming asemiconductor layer on a gate signal line and by forming a drainelectrode and a source electrode on the semiconductor layer, connectsthe drain electrode with a video signal line, and connects the sourceelectrode with a pixel electrode in a connecting region, the improvementbeing characterized in that the gate signal line sets a width thereoflarger at a portion where the TFT is formed than a crossing portion withthe video signal line and in the vicinity of the connecting portion.

<<C: Common Signal Line and Common Electrode>>

(C-1) A display device in which the display device includes a commonsignal line and a common electrode formed on a layer different from alayer on which the common signal line is formed, and the common signalline and the common electrode are directly connected to each other, theimprovement being characterized in that the common signal line is formedabove the common electrode and is arranged in a state that an endportion or an end side of the common electrode falls within a width ofthe common signal line.

(C-2) A display device in which the display device includes a commonsignal line and a common electrode formed on a layer different from alayer on which the common signal line is formed and the common signalline and the common electrode are directly connected to each other, theimprovement being characterized in that the common signal line is formedabove the common electrode and is arranged in a state that an endportion of the common electrode is positioned in a midst portion of thecommon signal line in the width direction.

<<D: Connection of the Common Potentials of Upper and Lower Pixels>>

(D-1) A display device being characterized in that each pixel includes acommon electrode and a common signal line which extends through a groupof pixels which are arranged in the lateral direction in common, whereinthe common signal line is formed such that, at least one portion thereofis directly overlapped to the common electrode and, further, is arrangedon one of either an upper or lower side of the pixel and, on anotherside of the upper or lower side of the pixel, an island-like connectingportion which is connected to the common electrode is arranged and, theabove-mentioned common signal line and the above-mentioned connectingportion are connected by a bridge line which extends over a gate signalline.

(D-2) A display device being characterized in that each pixel includes acommon electrode and a common signal line which extends through a groupof pixels which are arranged in the lateral direction in common, abridge line which connects the neighboring pixels in the verticaldirection over a gate signal line is provided, wherein theabove-mentioned bridge line is connected to the above-mentioned commonelectrode by way of the common signal line and the above-mentionedcommon electrode and the bridge line are formed of a transparentelectrode and the above-mentioned common signal line is formed of metal.

(D-3) A display device being characterized in that, in the constitution(D-1), the above-mentioned common electrode and the bridge line areformed of a transparent electrode and the above-mentioned common signalline and the island-like connecting portion are formed of metal.

(D-4) A display device being characterized in that, in the constitution(D-2) or (D-3), the above-mentioned common electrode is brought intocontact with the above-mentioned common signal line from below.

(D-5) A display device being characterized in that, in the constitutions(D-2) to (D-4), the above-mentioned common electrode is brought intocontact with the island-like connecting portion in a lower layer.

(D-6) A display device being characterized in that, in any one of theconstitutions (D-1) to (D-5), a pixel electrode having a large number offine line-like portions or slit-like portions is arranged above thecommon electrode and the pixel electrode and the line bridge are formedon the same layer.

(D-7) A display device being characterized in that, in the constitutions(D-1) to (D-5), a pixel electrode having a plurality of fine line-likeportions or slit-like portions is arranged above the common electrodeand the pixel electrode and the bridge line are formed of a samematerial.

(D-8) A display device being characterized in that, in the constitution(D-7), the common electrode is also formed of the same material as thebridge line.

(D-9) A display device being characterized in that, in the constitutions(D-1) to (D-8), a connecting portion between the bridge line and thecommon electrode or the island-like connecting portion has a shape inwhich a corner portion thereof on the pixel electrode side is cut.

(D-10) A display device being characterized in that, in theconstitutions (D-1) to (D-8), a connecting portion between the pixelelectrode and the common electrode or an island-like connecting portionare overlapped to each other by way of three sides which are unparallelto each other.

<<E: Another Example of Pixel>>

(E-1) A display device being characterized in that, each pixel includesa planar common electrode and a pixel electrode which is overlapped tothe common electrode and has a large number of fine line-like portionsor slits, the direction of the fine line-like portions or slits formedin the pixel electrode differs between an upper region and a lowerregion of each pixel, wherein the slits are directed downwardly as theslits extend toward one side surface of the pixel in the upper regionand are directed upwardly as the slits extend in the same one sidedirection of the pixel in the lower region thus arranging the slits inthe directions as if the slits converge toward the center, a commonsignal line is provided to the pixels which are arranged close to eachother in the lateral direction in common, the common electrodes areconnected with the common signal line, and the display device includes abridge line which electrically connects the common electrodes of thepixels which are arranged close to each other in the vertical direction.

(E-2) A display device being characterized in that, in the constitution(E-1), the bridge line is formed on the side toward which the slitsconverge.

(E-3) A display device being characterized in that, in the constitution(E-2), the common potential connecting portions are respectively formedcorresponding to upper and lower end portions of the side toward whichthe slits converge.

(E-4) A display device being characterized in that, each pixel includesa planar common electrode and a pixel electrode which is overlapped tothe common electrode and has a large number of fine line-like portionsor slits, the direction of the fine line-like portions or slits formedin the pixel electrode differs between an upper region and a lowerregion of each pixel, wherein the slit is directed downwardly as theslits extend toward one side surface of the pixel in the upper regionand is directed upwardly as the slits extend in the same one sidesurface of the pixel in the lower region thus arranging the slits in thedirection as if the slits converge toward the center and the displaydevice has a pattern in which the pixel electrode repeats theenlargement and the contraction of a width thereof at least three timesin a center region of the pixel electrode.

(E-5) In (E-4), a black screen is periodically displayed.

(E-6) A display device being characterized in that, each pixel includesa planar common electrode and a pixel electrode which is overlapped tothe common electrode and has a large number of fine line-like portionsor slits, the direction of the fine line-like portions or slits formedin the pixel electrode differs between an upper region and a lowerregion of each pixel, wherein the slits are directed downwardly as theslits extend toward one side surface of the pixel in the upper regionand are directed upwardly as the slits extend in the same one sidesurface of the pixel in the lower region thus arranging the upward slitsand the downward slits in a state that the upward slits and the downwardslits are alternately meshed with each other in a center region of thepixel.

<<F: Dummy Pixel Region>>

(F-1) A display device being characterized in that the display deviceincludes a plurality of pixels in the inside of the display region and adummy region arranged in an outer periphery of the display region,wherein the respective pixels at corner portions in the inside of thedisplay region have electrodes which are arranged in a state that thepixels hardly receives the influence of an electric field from the dummypixels at the corner portions.

(F-2) A display device being characterized in that the display deviceincludes a plurality of pixels in the inside of the display region and adummy region which is arranged on an outer periphery of the displayregion, an electrode which constitutes an uppermost layer on a substrateincludes line-like electrodes or slits and the directions of theline-like electrodes or the slits are equal between the pixels which arearranged at corner portions which face each other in an opposed mannerwith respect to the center of a screen, and at least in the vicinity ofthe corner portions.

(F-3) A display device being characterized in that, in the constitution(F-2), the direction of the line-like electrodes or the slits differsbetween the pixels which are arranged in a most-spaced-apart manner fromeach other on the same side and at least in the vicinity of the cornerportions.

(F-4) A display device being characterized in that the display deviceincludes a plurality of pixels in the inside of the display region and adummy region which is arranged on an outer periphery of the displayregion, the display device includes two types of pixels in which anuppermost electrode formed on the substrate includes line-likeelectrodes or slits and the directions of the line-like electrodes orthe slits differ from each other, and with respect to the direction ofthe linear electrodes or slits formed in the pixels at the cornerportions, by comparing an acute intersecting angle which the directionof the line-like electrodes or the slits makes with respect to a linewhich connects the corner portion and the center of the display region,the pixels having the direction of the slits or the electrodes whichintersects with an angle larger than the acute intersecting angle arearranged.

<<G: Dummy Pattern>>

(G-1) A display device being characterized in that the display deviceincludes a plurality of pixels in the inside of the display region and adummy region arranged in an outer periphery of the display region,wherein dummy pixels for film thickness measurement are arranged in thedummy region which is arranged closest to the display region.

(G-2) A display device being characterized in that, in the constitution(G-1), the dummy pixels for film thickness measurement have a largernumber of holes formed in protective films thereof than the number ofholes formed in protective films of other neighboring dummy pixels.

(G-3) A display device being characterized in that, in the constitution(G-2), there exists a plurality of types of dummy patterns havingdifferent layer structures.

<<H: Module Joining Structure>>

(H-1) A display device being characterized in that the display deviceincludes an upper frame, an intermediate frame and a lower frame,wherein the respective upper frame and the intermediate frame areindividually combined with respect to the lower frame.

(H-2) A display device in which the combination portion of the upperframe and the lower frame is not observed from a side surface on a longside of the display device and is observed from a side surface on ashort side.

<<I: Inverter>>

(I-1) A display device being characterized in that the display deviceincludes an inverter printed circuit board which is fixed to a metalframe, an inverter cover made of metal which covers the inverter printedcircuit board, a controller printed circuit board which is fixed to theabove-mentioned metal frame and the controller cover made of metal whichcovers the controller printed circuit board, wherein a large number ofholes are formed in both of the above-mentioned inverter cover and thecontroller cover and the size of the hole of the inverter cover islarger than the size of the holes formed in the controller cover.

(I-2) A display device being characterized in that the display deviceincludes a high-voltage side inverter printed circuit board and alow-voltage side inverter printed circuit board which are fixed to ametal frame, wherein an inverter transformer is arranged at thehigh-voltage side and the high-voltage side inverter printed circuitboard and the low-voltage side inverter printed circuit board arearranged at the end portions of the metal frame facing to each otherand, at the same time, are connected by the connecting member.

(I-3) A display device being characterized in that, in the constitution(I-2), the size of the high-voltage side inverter printed circuit boardis larger than the size of the low-voltage side inverter printed circuitboard.

(I-4) A display device being characterized in that, in the constitution(I-2) or (I-3), the number of the low-voltage side inverter printedcircuit boards are larger than the number of the high-voltage sideinverter printed circuit boards.

(I-5) A display device being characterized in that the display deviceincludes a high-voltage side inverter printed circuit board and alow-voltage side inverter printed circuit board which are fixed to ametal frame, wherein an inverter transformer is arranged at thehigh-voltage side and the metal frame includes a fixing portion of thehigh-voltage side inverter printed circuit board and the low-voltageside inverter printed circuit board, whereby the fixing portions arearranged in a fixable state even when the high-voltage side inverterprinted circuit board and the low-voltage side inverter printed circuitboard are replaced.

(I-6) A display device being characterized in that, in the constitution(I-5), the fixing portions are arranged on the both sides of thesubstrate with respect to the high-voltage side inverter printed circuitboard and are arranged on one side of the substrate with respect to thelow-voltage side inverter printed circuit board.

(I-7) A display device being characterized in that, in the constitution(I-6), the width of the low-voltage side inverter printed circuit boardis equal to or less than ½ of the width of the high-voltage sideinverter printed circuit board.

(I-8) A display device being characterized in that, in the constitution(I-7), the width of the low-voltage side inverter printed circuit boardis equal to or less than ⅓ of the width of the high-voltage sideinverter printed circuit board.

<<J: Fixing of the Upper and the Lower Frame>>

(J-1) A display device being characterized in that the display deviceincludes an upper frame, an intermediate frame and a lower frame,wherein, in a connecting portion of the upper frame and the lower frame,the upper frame has a projecting portion on a lower side thereof, thelower frame has a projecting portion on an upper side thereof and theintermediate frame has a hole portion formed therein.

(J-2) A display device being characterized in that, in the constitution(J-1), the upper frame and the lower frame are directly brought intocontact to with each other in the above-mentioned hole portion.

(J-3) A display device being characterized in that, in the constitution(J-2), the upper frame and the lower frame are fixed to each other inthe above-mentioned hole portion using screws.

(J-4) A display device being characterized in that the display deviceincludes an upper frame, an intermediate frame and a lower frame,wherein the upper projecting portion and the lower projecting portionare integrally formed on the intermediate frame, a hole is formed in theupper frame corresponding to the upper projecting portion, a hole isformed in the lower frame corresponding to the lower projecting portionand the above-mentioned upper projecting portion and the lowerprojecting portion are arranged in a state positions of the projectingportions are displaced from each other.

<<K: Intermediate Frame>>

(K-1) A display device being characterized in that the display deviceincludes an upper frame, an intermediate frame and a lower frame,wherein the intermediate frame is formed of a resin member and isdivided into four members consisting of a right member, a left member,an upper member and a lower member, and all of these four members areindependent from each other and the respective members are individuallyfixed to the lower frame.

(K-2) A display device being characterized in that, in the constitution(K-1), the upper frame and the lower frame are made of metal.

(K-3) A display device being characterized in that the display deviceincludes an upper frame, an intermediate frame and a lower frame,wherein the intermediate frame is formed of a resin member, is dividedinto four members consisting of a right member, a left member, an uppermember and a lower member, and all of these four members are independentfrom each other, these four members are configured such that the uppermember and the lower member extend only in the longitudinal direction ofa display device and the right member and the left member extend in bothof the lateral direction and the longitudinal direction of the displaydevice, and a length of a longitudinal portion of the display device isset shorter than a length of lateral portion of the display device.

(K-4) A display device being characterized in that, in the constitution(K-3), a display element is arranged between the upper frame and theintermediate frame.

(K-5) A display device being characterized in that, in the constitution(K-4), the right member and the left member are prevented from beingbrought into contact with a substrate end portion of the display elementin the short-side direction.

(K-6) A display device being characterized in that, in the constitution(K-4), a horizontal distance between the right member and the leftmember at a same height with an end portion of the display element inthe vertical direction of the display device is set longer than ahorizontal distance between the upper member and the lower member at asame height with the end portion of the display element.

(K-7) A display device being characterized in that, in the constitution(K-1), the members which are arranged close to each other are arrangedin a state that the projecting portions thereof in the horizontaldirection are fitted into each other.

(K-8) A display device being characterized in that, in the constitution(K-7), in the fitting portions, the respective members which arearranged close to each other are fixed to the lower frame using screws.

<<L: Drain Printed Circuit Board>>

(L-1) A display device in which the display device includes a displayelement, a driver element which is connected to the display element anda drain printed circuit board which is connected with the driverelement, the improvement being characterized in that two connectingmembers from a controller printed circuit board are connected to thedrain printed circuit board, a width of one connecting member is setlarger than a width of other connecting member, and the number of layersof another connecting member is set larger than the number of the layersof one connecting member.

(L-2) A display device being characterized in that, in the constitution(L-1), the above-mentioned one connecting member supplies a gray scalepower source and a power source for a video signal drive circuit andother connecting member transmits clocks and display data.

(L-3) A display device being characterized in that, in the constitution(L-1) or (L-2), the drain printed circuit board is divided in two andeach divided printed circuit board includes the above-mentioned oneconnecting member and the above-mentioned another connecting member andthe connecting members are arranged such that another connecting memberof both of printed circuit boards is arranged in the inside of oneconnecting member of both printed circuit boards.

(L-4) A display device including an upper frame made of metal, anintermediate frame made of resin and a lower frame made of metal, theimprovement being characterized in that the display device includes adisplay element, a driver element which is connected to the displayelement and drain printed circuit boards which are connected to thedriver element, wherein the drain printed circuit boards are provided inplural numbers, and the respective drain printed circuit boards arefixed to the above-mentioned lower frame using screws.

(L-5) A display device including an upper frame made of metal, anintermediate frame made of resin and a lower frame made of metal, theimprovement being characterized in that the display device includes adisplay element, a driver element which is connected to the displayelement and a drain printed circuit board which is connected to thedriver element, wherein the drain printed circuit board is arrangedbetween a bent side surface portion of the lower frame and a bent sidesurface portion of the upper frame.

<<M: Inverter Cable>>

(M-1) A display device including an inverter, a light source and a cablewhich connects the light source and the inverter, the improvement beingcharacterized in that the display device includes a holding member whichis integrally formed with a mold which fixes the light source, theabove-mentioned cable is arranged in a region sandwiched between a sidesurface of the mold and the holding member thus restricting the movementof the cable in the fore-and-aft direction and, further, the cable isarranged along an arcuate R portion which is formed above the holdingmember and is constituted such that the cable is restored again to alower side of the R portion and, thereafter, connected to the lightsource.

<<N: Reflection Sheet>>

(N-1) A display device including a lower frame, a reflection sheet, alight source, a diffusion plate and a display element, the improvementbeing characterized in that the reflection sheet is arranged between thelower frame and the light source, the diffusion plate is arrangedbetween the light source and the display elements, the lower frame isformed in an approximately planar shape in a region below the displayelement and the lower frame is raised upwardly in a peripheral portionof the display element and extends horizontally and, a horizontalportion has a hole formed therein, the reflection sheet is arrangedapproximately horizontally in a region below the display element, isbent in an oblique direction at a peripheral portion thereof and isextended upwardly and, thereafter, is extended horizontally and,further, a portion of an end portion of the sheet is bent downwardly andis fitted into a hole formed in a horizontal portion of the lower frame.

(N-2) A display device being characterized in that, in the constitution(N-1), the above-mentioned reflection sheet is sandwiched between adiffusion plate and the lower frame thus preventing the removal of thereflection sheet from the hole portion.

(N-3) A display device being characterized in that the display deviceincludes an upper frame, an intermediate frame, a lower frame, a lightsource and a side mold to which the light source is fixed, wherein theabove-mentioned upper frame, the intermediate frame, lower frame andside mold are independently fixed to the above-mentioned lower frame.

(N-4) A display device being characterized in that, in the constitution(N-3), the fixing is performed using screws.

<<P: Light Source>>

(P-1) A display device including a light source, a lower frame made ofmetal which is arranged below the light source, a display element whichis arranged above the light source, the improvement being characterizedin that a plurality of light sources are arranged in parallel and commonspacers are arranged to longitudinally cross some of the plurality oflight sources between the lower frame and the light source.

(P-2) A display device being characterized in that, in the constitution(P-1), the common spacers are formed of an elastic or resilient member.

(P-3) A display device being characterized in that, in the constitution(P-2), the common spacers are made of rubber or sponge.

(P-4) A display device being characterized in that, in the constitution(P-1), a reflection sheet is arranged between the common spacers and thelight sources.

(P-5) A display device being characterized in that, in the constitution(P-1), the light source is a fluorescent tube, the fluorescent tubeincludes a side which is connected to a high-voltage side of an inverterand a side which is connected to a low-voltage side of the inverter andthe above-mentioned common spacers are arranged on the high-voltageside.

(P-6) A display device being characterized in that, in the constitution(P-1), the light source is a fluorescent tube and the above-mentionedcommon spacers are collectively arranged on the whole fluorescent tube.

<<Q: γ Characteristics>>

(Q-1) A display device in which a signal from the outside of the displaydevice is inputted to a controller and the controller supplies a videosignal to a video signal drive circuit after processing the signal, theimprovement being characterized in that a gray scale reference voltagewhich is supplied to a video signal line drive circuit is generated by aD/A converter in response to an instruction from the controller.

(Q-2) A display device being characterized in that, in the constitution(Q-1), the above-mentioned gray scale reference voltage is variable inplural kinds in response to the instruction of the controller.

(Q-3) A display device being characterized in that, in the constitution(Q-2), the video signal line drive circuit generates a voltage per eachgray scale based on the gray scale reference voltage.

(Q-4) A display device being characterized in that, in the constitution(Q-3), the display device includes a memory which can supply informationto the controller, and the above-mentioned memory holds a plurality ofdata sets for changing the gray scale characteristics.

(Q-5) A display device being characterized in that, in the constitution(Q-4), the above-mentioned data set is selectable in response to asignal from the outside.

(Q-6) A display device being characterized in that, in the constitution(Q-4) or (Q-5), a power source voltage for operating the circuit per seis supplied to the video signal line drive circuit, the rising sequenceat the time of supplying the gray scale reference voltage to the videosignal line drive circuit from the above-mentioned D/A converter isperformed such that, as the time elapses, first of all, a power sourcevoltage of the video signal line drive circuit is raised firstly and,before the power source voltage of the video signal line drive circuitreaches a steady state, the supply of the gray scale reference voltageis started. Thereafter, when the power source voltage of the videosignal line drive circuit reaches the steady state, the gray scalereference voltage is allowed to assume the steady state.

<<R: Display of Manufacturing Information>>

(R-1) A display device including a display element and a controllerwhich allows the display element to display a signal in response to asignal from the outside, the improvement being characterized in that thedisplay device includes a memory, and the above-mentioned controller hasan information display mode in which the display element is allowed todisplay information set in the above-mentioned memory.

(R-2) A display device being characterized in that, in the constitution(R-1), the changeover to the information display mode is performedcorresponding to whether an output is released from one terminal of thecontroller or the short-circuiting occurs.

(R-3) A display device being characterized in that, in the constitution(R-1) or (R-2), the information displayed in the information displaymode is a barcode.

(R-4) A display device being characterized in that, in the constitution(R-1) or (R-2), the information displayed in the information displaymode is a strip-like image.

(R-5) A display device being characterized in that, in the constitution(R-4), the strips include strips which differ in color.

<<S: Changeover of the Display Frequency>>

(S-1) A display device including a display element and a controllerwhich allows the display element to display a signal in response to asignal from the outside, the improvement being characterized in that thedisplay elements are able to perform a display in a plurality offrequencies and the changeover of the frequency can be instructed inresponse to a mode change signal from the outside, the display deviceincludes a memory which temporarily stores image information and, whenthe controller receives the mode change signal, the controller examinesboth changeover timings of the plurality of display modes havingdifferent frequencies, and the controller executes the mode change whenthe timings are synchronized with each other and, when the timings arenot synchronized with each other, postpones the mode change until thetimings are synchronized with each other.

(S-2) A display device being characterized in that, in the constitution(S-1), out of two display modes having different frequencies, onedisplay mode is a mode which periodically displays a black image bysetting a high frequency and another display mode is a mode in which thefrequency is low and the input frequency from the outside and thedisplay frequency coincide with each other.

<<T: Resistance Measurement of the Connecting Portion>>

(T-1) A display device in which the display device includes a displayelement, a tape carrier and a printed circuit board, and a signal fromthe printed circuit board is transmitted to a display element in a statethat a terminal on the printed circuit board and a terminal on the tapecarrier are connected with each other at a first connecting portion, thesignal is transmitted through a line on the tape carrier, and a terminalon the opposite side of the tape carrier and a terminal of the displayelement are connected with each other at a second connecting portion,the improvement being characterized in that the connection resistanceeither at the first connecting portion and the second connecting portionis measurable using a measuring terminal formed on the printed circuitboard.

(T-2) A display device being characterized in that, in the constitution(T-1), the above-mentioned measurement can be performed under conditionsof a four terminal method.

(T-3) A display device being characterized in that, in the constitution(T-1), the above-mentioned first connecting portion or the secondconnecting portion is connected by way of an anisotropic conductivefilm.

(T-4) A display device in which the display device includes a displayelement, a tape carrier and a printed circuit board, and a signal fromthe printed circuit board is transmitted to a display element in a statethat a terminal on the printed circuit board and a terminal on the tapecarrier are connected with each other at a first connecting portion, thesignal is transmitted through a line on the tape carrier, and a terminalon the opposite side of the tape carrier and a terminal of the displayelement are connected with each other at a second connecting portion,the improvement being characterized in that a common potential line busis arranged at the display element, the tape carrier and the displayelement are connected separately at two places and, at the same time,are respectively connected to the common potential line bus separately,one out of these wirings is divided on the tape carrier and,accordingly, the tape carrier and the printed circuit board arerespectively connected at three places, the wiring which is divided onthe tape carrier is further divided on the printed circuit board and themeasurement terminals corresponding to the above-mentioned respectivewirings which are divided are arranged on the printed circuit board.

(T-5) A display device in which the display device includes a displayelement, a tape carrier and a printed circuit board, and a signal fromthe printed circuit board is transmitted to a display device in a statethat a terminal on the printed circuit board and a terminal on the tapecarrier are connected with each other at a first connecting portion, thesignal is transmitted through a line on the tape carrier, and a terminalon the opposite side of the tape carrier and a terminal of the displayelement are connected with each other at a second connecting portion,the improvement being characterized in that the common potential linebus on the display element is also used as the common potentialsupplying bus line, the respective tape carriers include commonpotential supply lines which does not go through the driver element, thesupply line is connected to the common potential line bus on the displayelement and is connected to the common bus line again which is formed onthe printed circuit board, the common potential supply line has ameasurement terminal thereof on the printed circuit board and isconnected to the common potential line bus again and extends on the tapecarrier and, thereafter, a measurement wiring which is connected to theprinted circuit board is formed and a measurement terminal is formed onthe printed circuit board and, the measurement wiring increase thenumber thereof by sequentially being divided on the tape carrier and onthe printed circuit board and each of the divided wiring has ameasurement terminal formed on the printed circuit board.

(T-6) A display device being characterized in that, in the constitution(T-5), out of the wirings which are connected to the measurementterminals, the wirings except for the common potential supply lines areseparated from the reference potential supply line on the printedcircuit board.

1. A display device includes, a common electrode has a rectangle sharp,a pixel electrode which is overlapped to the common electrode and has aplurality of slits, the direction of the slits formed differs between anupper region and a lower region of each pixel, the slit has theinclination which is not parallel to a gating signal line and the videosignal line, the Inclination of the slit is symmetrically formedfocusing on the center of the pixel region, a common signal line isformed in parallel with the gating signal line, the common signal lineare connected with the common electrodes, and a bridge line whichconnects the common electrode of the pixel region which adjoins in thedirection parallel to the gating signal line.
 2. A display deviceaccording to claim 1, the bridge line is formed on the side toward whichthe slits converge.
 3. A display device according to claim 2, the commonsignal line is formed on the position of the connecting area of thebridge line and the common electrode.
 4. A display device has aplurality of pixel region, each pixel includes a common electrode has arectangle sharp, a pixel electrode which is overlapped to the commonelectrode and has a plurality of slits, the direction of the slitsformed in the pixel electrode differs between an upper region and alower region of each pixel, the slit has the inclination which is notparallel to a gating signal line and the video signal line, theInclination of the slit is symmetrically formed focusing on the centerof the pixel region, at least three slits are foamed symmetrically inthe center of the pixel region.
 5. A display device according to claim4, the display device displays a black picture periodically.
 6. Adisplay device has a plurality of pixel region, each pixel includes acommon electrode has a rectangle sharp, a pixel electrode which isoverlapped to the common electrode and has a plurality of slits, thedirection of the slits formed in the pixel electrode differs between anupper region and a lower region of each pixel region, the slit of theupper region and the slit of the lower region are arranged in the centerof the pixel region to be engaged in turn.